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siGooi^le
siGooi^le
AN raTEODUCTION
PRACTICAL CHEMISTRY.
siGooi^le
siGooi^le
AN INTROlinCTION
PEACTICAL CHEMISTRY,
INCLUDING ANALYSIS.
JOHN E. BOWMAN, F.C.S.,
SECOND AMERICAN,
PHILADELPHIA;
SLANCHAED AND LEA.
18.56.
siGooi^le
siGooi^le
PREFACE
TO THE SECOND EDITION,
In the present Edition I have endeavored, as far as
possible, to make this little work more fully adapted to
the rec[uire!nent3 of the general student ; and I believe
it now leaves little to be desired as an Introdnetoiy
Text-hook of Practical Chemistry. I have also, without
adding niateriallj to its bulk, embodied such changes
and corrections as have been rendered neceesaiy by the
progress of the science since the first edition was pub-
lished.
J. E. Bowman.
King's C0LI.KOE, Loniion, Febi'iiary, 185*.
=vGoo(^lc
siGooi^le
PEBPACE
TO THE riKST EDITION.
Among the many recent and valuable works on Clie-
miatry, I am not aware of one having for its special
object to explain, and render simple to the beginner, the
various processes employed in analysis, or which have
been devised for the illustration of the principles of the
Science. Most of them contain much that is superfluous
for the general student, who has but a limited time to
devote to the subject ; while they are wanting in those
explanatory details, without which he must often fail to
understand the rationale of the operations throngli
vi'hich he is conducted.
It is with a wish to supply this deficiency, and at the
same time to furnish a test-book for my own classes,
that the present little work has been written ; and as It
is intended for the use of those who have made but little
progress in the Science, my endeavor has been, through
out, to make everything as simple and intelligible as
possible. The employment of complicated or expensive
apparatus has been almost wholly avoided.
=vGoo(^lc
viil PREFACE.
The oiitline of most of the First Part was arranged
some years ago by my friend Professor Miller (at that
time Demonstrator of Chemistry in King's College), for
the use and direction of the class of Chemical Manipu-
lation, then iiret established to supply a gi'omng de-
mand, and to meet the requirements of the TJniveraity
of London, and some of the other examining Boards of
the Metropolis, In the compilation of the Second and
Third Parte, I have been much indebted to the excellent
works of Eose, Fresenius, Pamell, and others ; I must
also here thank my colleague, whose name I have al-
ready mentioned, for many valuable suggestions, and for
his kindness in revising the proof sheets, without which
assistance many errors would have crept in, and rendered
the book less worthy of the student's confidence.
John E. Bowman.
Kiso's Colli:re, Losdos, September, 1848.
siGooi^le
CONTENTS.
I.NTfiODVOTORY, ....
Importance of Experimental Chemistry, .
Chemical Symbols and Equations,
General Rules, &c.
CHAPTER IT.
Phbumatic Chemistry,
Skction 1, Hydrogen,
2. Cwljouic Aciti, .
3. Binoxide of Nitrogen,
4. defiant Gas,
5. Carbonic Oxi<!e,
(i. Oxygen, .
'}, Hydrochloric Acid Oa;
R. Ammonlacal Gaa,
CHAPTER HI.
Section 1. Watej',
2. Hydrochloric Acid,
3. Ammotiia,
4. Nitric Acid, .
=vGoo(^lc
CONTENT 3,
CHAPTER IV.
Glass Working,
EsFERlMENTS IV
CtlAPTEU V.
K Mouth Bt.oivpipk, .
CHAPTER VI.
Specific Gbavitv,
Sectiok 1. Of Solids heavier than Water,
2. Of Solida Jigliter than Water,
3. Of Insohible Powders,
4. OfLiqnids,
CHAPTER VH.
SsoTKh 1 Eeduotion of Metallic Oxides by Hydrogen,
_ Heiting m vt Atmosphere of Ciirboniij Acid,
■i Piepavation of Perehloride of Iron,
CHAPTER VIII.
AT.KALIMETHY and ACIDIMETIIY, ....
Section' 1. AUcalimetry, ....
2. Acidimetrj, .....
3. Estimation of Carbonic Acid in Carbonates,
PART II.
THE AOTIOR OP REAGBNTS ON BASES AND ACIDS.
CHAPTER I.
Section 1. letroSuctory, .....
2. Classification of Bases and Acids,
siGooi^le
C N T B K T S.
CHAPTER 11.
Metals bki.onging to Class 1,
Sectiok 1. Potasb, .
3. Ammoiiia,,
CHAPTER 111.
Mbtais bei^nging to Class II,
Seciiok 1. Magnesia,
2. 1
4. Strontik,
9R
CIIAPTEE IV.
Class III,
3. CliromiuiB,
3. Oxide of Zinc,
4. Protoxide of Mangaii
5. Protoxida of Ifon,
(). Peroxide of (i.-ouj
7. Oxide of Niclfel,
8. 0.-iide of Cobalt, .
CHAPTER V.
ASS IV, .
Sectiox 1. Arsenic, .
2. Antimony,
3. Protojcide of Meicui-y,
4. Peroxide of Mercuty,
5. Oxide of Lead, .
G. Oxide of Copper,
r. Oxide of Silver,
8. Protoxide of Tin, .
9. Peroxide of Tin,
10. Oxide of BisiButh, .
=vGoo(^lc
CONTENTS.
CHAPTER VI.
Acids,
Section 1. Sulphuric Aoiil,
2. PhoiSpliorie Acid,
3. Boracic Acid,
4. Carbonic Aeid, .
6. Silicic Acid,
6. Hydrochloric Acii],
1. Hjdriodio Acid,
8. Hydrosnlplinrie Acid
9. Nitric Acid, .
10. Cliloric Acid,
(JHAFrER VII.
OuGAHic Aciua, ....... I'19
Section 1. Osalic Acid, ..... 150
2. Tai-tarie Acid, , . . . . lol
3. Cilric Acid, !j3
4. Malic Acid, . . . . . . 1 54
5. Sueeinic Add, , . . . . 1 55
G. Benzoic Acid, . . . . .155
7. Acetic Acid, , , . . .151;
.S. Formic Acid, U'i'f
QUALITATIVE ANALYSIS OF SUBSTANCES, THE COMPOSITION
OF WHICH IS unknown.
CHAPTER I.
PREMHINAlir EXAMINAT10^, &t ...
Sectios 1. Prelimmiiy Examination of Solids,
2. Prehimnary Evaminatiun of Liquids,
!i. lutioduciorj Remirk'* un the aeiual Analysis,
siGooi^le
C S T E N T (?.
CHAPTER II.
hi- Acid,
CHAPTEll III.
OiLlTAinC A-IALY^ri L
IN WiTEtt, nnT li
P A SIMPLE Salt,
)LUEi.G IK Acids,
Skction I Cximmiti
2 Eximmit:
lu foL Base,
311 fui' Acid, .
CHAPTER IV.
UALITATIVB ANALYSIS
umn If Water a
■p A SIMPLE Salt,
.ND Auins,
CHAPTER V.
iL-iLiTATivii AsALrsia <
)F A MI.-VTL-EB OF .
List. Introductout Bemaiiks,
CHAPTER VI.
.ITATIVK AkALYSIB OF A MlXTDllE OF
CHAPTER Vil.
=vGoo(^lc
CONTENTS.
CHAPTER VIU.
.' SaltH, INSOTrDliLR IX
W.ii'Eit AND Acids,
PART IV.
QUANTITATIVE ANALYSIS.
Pulverization,
Drpng, .
Weighing,
Solution,
Precipitation,
Filtration,
Decaiitation,
Evapciratiou, .
Calculation of Results,
CHAPTER II.
Sectios 1. Quantitative Analysia of Sulphate of Coppei', . '.
2. Quantitative Analysis of CUoride of Potassium, , '.
3. Quantitative Analysis of a Mixture of Sulphate of
Copper and Chloride of Sodium, . . 2
4. Quantitative Analysia of a Mixture of Sulphate of
Zinc and Cajbonatfl of Baryta, . . . »
6. Quantitative Analysis of Magnesiau Limestone, . '•
6. Quantitative Analysis of Copper Pyrites, , . 1
=vGoo(^lc
Sulphuric Add,
Hydcoolilorio Acid,
Nitric Acid, .
Nitrobydroclilorie Acid [J
Hydrosulphuric Acid,
Oxalic Acid,
Acetic Acid, ,
Tartaric Acid, .
Aimnonia,
Hydrosulphateof Amuioi
Carbonate of Ammonia,
Oxalate of Ammonia,
Phosphate of Soda and A
Potash, .
Carbonate of Potash, .
Nitrate of Potash,
Iodide of Potassium, .
Ohramate of Potash,
Cyanide of Potassium,
If'ei.'rocyanide ol Potasaiun
PeiTldcyanide of Pota^^ii
Antlmoniate of Potash,
Carbonate of Soda,
PliosphateofSoda,
Boras,
Lime Water,
Sulphate of Lime,
Clilorido of Calcium,
Chloride of Baiiam, .
Nitrate of Baryta,
Perchlorideof Iron, .
Nitrate of Cobalt,
Sulphate of Copper, .
Acetate of Lead, .
SubacetateofLead, .
Nitrate of Silver, .
Aramonio-nitrate of Silve
Perchloride of Mercury,
CHAPTER I
l-qua Eegia),
nimonia,, .
23
23
23
23
■23
23
23
2:i
23
24
24
24
24
24
24
24
2i
24
24
24
24
34
24
24
24
24
24
24
24
24
24
24
24
24
25
25
Gooi^le
Protocliloride of Tin, .....
Perchloride of Gold, , . . ,
Bichloride of Platinum, . . . .
Salpliate of ludigo, ....
Staceh, ......
Black Flux, .....
Distilled Waier, .....
Alcohol, ......
APPENDIX.
Wetghts and Meastjbbs, ....
Troy or Apothecaries' Weight, .
Avoirdu[>oia Weight, ....
Imperial Meaisure, ....
Weight of Water coiitaiued in the Inipeiial Measure,
Cubic inches contained in the Impevial Measure,
French WEienTs and MEisunna,
Measures of Length, ....
Measures of Capacily. ....
Table showing the strengtliof Sulphuric Acids of different densities, 2
Table stowing tiie strength of Nitric Acids of different densities, . 2
Table showing the strength of Hydrochloric Acid of different densi-
ties, 2
Table showing the strength of Solution of Potasli of different densi-
Table showing the strength of Solution of Soda of different densi-
Table showing the strength of Liquid Ammonia of different densi-
Table showing the strength of Alcohol of different densities, i
Table showing the strength of Ether of different densities, - . i
Table showing the Solubility of Salts, . . . . i
Table showing the action of Reagents on Oxides and Acids, , i
Table showing the behavior of Solutions of the Mefala with Hydro-
sulphuric Acid, HydTOSolphate of Aramonia, and Carbonate of
AmmOiiia, ....... 1
List of Salts, &c,, whicli may be exaiuined tor practice in Qualita-
tive Analysis, . . • • . . i
Glossary of Chemical Terms, , . , . ;
=vGoo(^lc
PRACTICAL CHEMISTRY.
PAKT I.
CHAPTER I.
INTRODUCTORY — SYMBOLS — EQUATIONS — GENERAL RULES.
1. So essentially is chemistry an experimental science,
and so almost exclusively is it built up of facta which
have "been elucidated by experiment, that vi-itbout ex-
perimental illustrations it would be quite impossible to
teach or to study it with any great amount of success.
It is not enough, however, for the student to see eK-
periments performed by others ; he must, if he would
master, even the general principles of chemistry, learn
to make experiments himself; and he will, probably, be
surprised how much more easily he will retain in his
recollection those phenomena (as well as the prineiplea
they illlistrate) which his own hands have been the
means of producing. This is especially the case when
he is enabled, while operating in the laboratoiy, to learn
and study the theory of the changes which take place
under his direction.
2. With the view of enabling the beginner to do this
as much as possible, I have in the following pages ex-
plained, by means of chemical symbols and equations,
nearly the whole of the changes and decompositions
which take place in the experiments described. The
symbols which I have made use of are those now almost
universally adopted by chemists ; and it wiU be seen by
the following Table, that they consist, for the most part,
of the firstletter or two letters of the Latin names of the
elements which they express.
=vGoo(^lc
AND EQUrVALESl
Ibble of Elementary
their sj/mbols, atomic
compounds.
[arranged oJ^habeficaMt/), shotoing
and tJie eomposition of some of their
NBine.
SsmM.
Waishl,
Cou,po,...
Aluminum, . .
Al
14
( AljO, Alumina.
JaIjC], Cliloride of aluminum.
^AljOsfSSOs Sulphate of alumina.
Antimony, . .
Sb
12B
(SbO, Oxide of antimony.
[SbOj Aiitimonic acid.
Arsenic, . . .
As
75
( AsO, Araenious acid.
) AsOj Arsenic acid.
Bai'iuTu, . . .
Ba
69
fBaO Baryta.
1 BaCl Chloride of Barium.
Bismuth, . . .
B.
107
(BioO, Oxide of bismuth.
JBiA>3NOs Nitrate of bismuth.
[BijGla Chloride of biamath.
Boron,. . . .
B
11
BO, Boraoic add.
Bromine, . . .
Jir
78
fSrO, Bromlcacid.
1 HBr Hydrobromic aeid.
Cadmium, . .
Cd
5S
fCdO Oxide of cadmium.
jCdS Sulphide of cadmium.
1 Ciilcium, . . .
Ca
20
( CaO Lime.
I CaCl Chloride of cakium.
i
Carbon, . . .
C
G
( CO Carbonic oxide.
J GOj Carbonic acid.
( CSi Sulphide of carbon.
Cerium, . . .
Ce
"1:1;
f CeO Oside of cerinm.
ICeA Sesquioxide of cerium.
Chlorine,. . .
CI
36
f CIO, Chloric acid.
J CIO, Perchloric acid.
t_HCl Hydrochloric acid.
Ghromlnm, . .
Cr
28
fCrOs Chromic acid.
i OrjOa Oxide of chromium.
(Crj03,3SOj Sulphate of chromium.
Cobalt, . . .
Co
30
f CoO Oxide of cobalt.
|CoA Sesquioxide of cobalt.
Copper, . . .
(Cnprum.)
Ou
S2
( CujO Suboxide of copper.
i CuO Black oxide of copper.
|CuO,SO, Sulphate of copper.
siGooi^le
SYMBOLS AND EQUIVALESTS.
K^. .,».„,.
vslght.
o..„.«..
Didjmmm, . .
D
7
?
Fluorine, . . .
F
18
f HF Hydrofluoric acid.
[bF, Muoboncacid.
Glucinum, . .
G-
7(?)
f GO5 Glucina.
JGCJ, Chloride of glueiuum.
Gold, ....
(Aurnm.)
Au
200
AuO Oxide of gold.
J AUO3 Teroxideofgold.
AuCla Terchlorideofgold.
Hydrogen, . .
H
1
f£-0(orJ9) Water.
tifO.Biiioside of hydrogen.
Iodine, . . .
I
i2e
f lOj Iodic acid.
\ HI Hydriodic acid.
Iridmm, . . .
Ir
99
f IrO Protoxide of ividium.
1 Ir^Oa Sesquioxide of iron.
Iro., ....
(Ferrura.)
]?e
38
fFeO Protosideofiron.
1 FbjO, Sesquioxide of iron.
L^thauum', .
Lu
48
LaO Oxide of lantianum.
Lead, ....
(Plumbum.)
Pb
104
( PbO Protoxide of lead.
J Pb,0, Red oxide oflead.
(.PbCi Chloride oflead.
Lithium, . , .
Li
1
( LiO Lithia.
(LiCl Chloride oflitMum.
Magneaium, . .
Mg
12
( MgO Mi^neak.
LMgOl Chloride of magnesium.
Manganese, . .
Mn
28
fMnO Protoxide of manganese.
J MnO, Binoxide or black oxide.
1 MnOj Manganic acid.
Mercury, . . .
U'J
202
f HgO Protoxide of mercury.
J HgOj Red oxide of mercury.
1 HgCl Protochloride of mercury.
[HgClj Perehloride of merouvy.
Moljbdeuum, .
Mo
48
MoO, Molybdic acid.
Nickel, . . .
Nl
30
(NiO Oxide of nickel.
iNijOj Sesquioxide of nickel.
Nitrogen, . . .
N
1-1.
( NO, Nifric acid.
JNOj Binoxide of nitrogen.
(NHj Ammonia.
siGooi^le
BOLS AND EQUIV^
Oxygen, .
Palladmm,
Phoapliorus,
Platinuro,
PotussiuDi,
(IMkm.)
Rhodium,
Eutheiiium, .
Selenium,
Silicon, .
(Nati'onium.)
Sti'ootium,
(OsO, Binoxide of osmium.
(PdO Pi-otoxide ofpiUadium
I PdOj Peroxide ot palladium
r PO5 Phosphoric acid
\ PO3 Phosphorous acid
J PtO Protoxide ot platiLmni
jPtOa Binoxide of platinnni
( KO Potash.
( KCl Chloride of potassium
1 RO Protoxide of rhodium
jBjOs Sesquioxide of rhodium
EujOs Sesquioxide ot ruthen u
i SeOa Selenic acid,
j HSe Hjdroselenic aeid.
SiOs Silicic acid.
1 AgO O-vide of silver,
j AgCl Chloride of silver.
j NaO Soda.
NaOl Cliloride of sodium.
(Stannuii
Titanium,
I TaO, Oxide of taotaliuii
( TeOe Tantalic acid,
J TeO, Telluric acid.
I HT Hjdrotelluric acid.
( ThO Oxide of thorium.
ThCl Chloride of thoriui
WOj TungstJc acid.
=vGoo(^lc
s,..,.
Weight.
c™,„....
Uranium, . .
Vanadium, . .
Yttrium, . . .
Zinc, ....
Zirconium, . .
U
V
T
Zn
Zr
60
69
32
32
34
f TJO Protoxide of ummum.
tUjOj Sesquioxide of uranium.
VO, Vanadic acid.
(YO Yttria.
(YCl CWoride of yttrium.
( ZnO Oxide of zinc.
jZnCl Chloride of Einc.
I ZrjO, Zirconia.
( ZrCI, Chloride of airconium.
3. Bacli of these symtols expresses one equivalent or
atom of the substance which it represents. Thus, H
stands for one atom or equivalent of hydrogen ; Cu for
an equivalent of copper ; Mg for one of mercury.
When a small figure is placed to the right of a sym-
bol, i-ather below vao line, it means that there is that
number of equivalents of the substance present. Thus,
Pb^ means two equivalents of lead ; O, five equivalents
of oxygen ; Hj,, ten equivalents of hydrogen.
Two or more symbols placed together, signify that
the elements which they represent are chemically united
in the closest manner. Thus HO stands for water, which
is a compound of one equivalent of hydrogen, and one
of oxygen; SOj represents anhydrous sulphuric acid,
composed of one equivalent of sulphur and three of
oxygen; Ci^Hj^Oig represents starch, which consists of
12 equivalents of carbon, 10 of hydrogen, and 10 of
oxygen, chemically combined together.
When symbols are separated by a comma, they repre-
sent compounds which are held together by a force less
strong than that which unites elements that have no
such mark interposed. Thus KO,SOs means sulphate
of potash, composed of potash and sulphuric acid. The
constituents of sulphate of potash, therefore, are both
compounds, and the affinity which unites the potassium
with the oxygen, and the sulphur with the three equi-
valents of the same element, is supposed to be stronger
than that which unites the acid with the base, since it
=vGoo(^lc
18 SYMBOLS.
is easier to break it up into potash aad sulphunc acid,
than into potassium, oxygen, and sulphur.
When the sign + ia interposed, it indicates that the
substances between whicli it ia placed are united in a
manner still less intimate. Thus, in crystallized car-
bonate of aoda{]sraO,OO2+10 Aq),'wehave sodium and
oxygea in the soda, and carbon and oxygen in the car-
bonic acid, combined in the closest and strongest
manner; the soda and eai'bonie acid thus formed are
separated by a comma, showing that they are held to-
gether by what we may here call the second degree of
affinity; while the 10 equivalents of waterof ciystalliza-
tion, separated by the sign +, are held by a much
weaker force, so feeble indeed that a very moderate heat
is sufficient to expel them.
The sign + is used also to separate the symbols of
substances which are entirely disunited, as when we
■wish to express a mixture of carbonate of lime and hy-
drochloric acid, we put it thus, Ca-OjGO^+S'Cl
A large figure placed immediately before a symbol,
multiplies all the symbols as far as the next comma or
-1- sign. Thus, in the common phosphate of soda
(2KaO,HO,P05) there are two equivalents of soda, one
of water and one of phosphoric acid, combined together.
If a large figure were placed before the whole formula
enclosed in brackets, thus, 5(2NaO,HO,P03) it would
represent 5 equivalents of the entire salt.
4. It is really wonderful how much these little sym-
bols are capable of expressing, and how otlcn and com-
pletely they assist in simplifying and rendering intel-
ligible even the most complicated chemical changes ;
for besides the information they convey relative to the
composition of the substances which the^y express, they
can be so combined in the form of equations, as to show
in the most perfect manner, the various compounds
which result during chemical decompositions. For this
pui-pose, the symbols of the substances employed are
placed together so as to form one side of the equation ;
on the other side are placed those of the substances
which ai'e produced during the decomposition ; and as
no atom of matter is lost during these transformations,
Ho:toa=vGoO(^lc
EQIJ" ATIOSS. 19
trily follows that the value of botli sides of the
eqaatioQ must be equal. For example, the decomposi-
tion of carbonate of lime by hydrocliloric acid may be
thus represented : —
Here we place the symbols of carbonate of lime and
hydrochloric acid on one side, and on the other those
of chloride of calcium, water, and carbonic acid, which
are produced during the decomposition ; and it will be
observed that on each side there are exactly the same
number of equivalents, viz. 1 of calcium, 3 of oxygen,
1 of carbon, 1 of hydrogen, and 1 of chlorine.
5. I have ventured to introduce a slight modification
of the usual mode of piinting the symbols, which will
enable the student to see at a glance whether the sub-
stances expressed are in the solid, liquid, or gaseous
form.
Those in the solid state ai-e printed in strong Roman
type, as Pb, lead. Liquids, or substances in solution,
ai'e printed in strong italics, as HO, water ; and gases
or vapors are represented by fine hair letters, as K hy-
drogen, HO, steam.
Thus in the above equation, liquid hydrochloric acid
(SOi) is poured on solid carbonate of lime {CaO,COj) ;
chloride of calcium (CaOl) is formed, which remains in
solution, together with carbonic acid (00^) which passes
oft" in the gaseous form.
6. It is very important that the student should at
once begin to make careful notes of all the experiments
he engages in. lie should endeavor to do this in as
concise and methodical a manner as possible, and he
will find it very advantageous to make use of symbols
in describing the substances he employs, and the
changes which they undergo : he will thus be able to
record much in a small space, and at the same time he
will be making himself familiar with the composition
of the substances with which he is experimenting.
7. When, as is often the case, especially in analytical
experiments, thei-e are several solutions and precipitates
either filtering, digesting, or waiting till the operator
has leisure to attend to thom, it is necessary to mark
=vGoo(^lc
20 CLEANLINESS — GENERAL ILULES.
tliem in someway, to preventconfnsiou. Thisia easily
done witli small pieces of gummed paper, on which a
letter or number may bo written, coiTesponding with a
similar reference raai'k: in the note-book.
8. The student will soon learn by experience that he
cannot be too methodical in his operations, or too care-
ful in cultivating habits of neatness and cleanliness.
The presence of a little saline or other impurity in a
glass, owing to careless washing, or a little extraneous
matter having been allowed to imd its way into a bottle
or test tube, may retard or spoil the result of whole
days of labor.
"Much as the chemist may soil his fingers during his
experimental occupations, he will soon learn the great
importance of cleanliness to the success of his experi-
ments. The regular course of his operations causes
many kinds of matter to pass in succession through his
hands ; and many of the substances, which by mixture
have exhibited the phenomena they were competent to
occasion, and so far answered the purpose of the experi-
ment, then become mere useless dirt- Their dismissal
and entire removal when thus circumstanced become
necessary, that they may not contaminate other bodies ;
and are as imperatively required, as was the care previ-
ously bestowed to prevent their contamination from ex-
traneous matter.
"It is this rapid change in the character and relation
of the substances with which the chemist works, that
makes a constant attention to cleanliness essentially
neeessaiy. The very bodies which at one moment are
carefully retained in vessels that have previously been
cleansed with the most scrupulous attention, become
the next in the situation of so much dirt, from which
the vessel must be cleansed as perfectly and carefully,
before they can he fit for another experiment, as they
were for the reception of the now rejected matter. The
results of numerous experiments relative to testing
bodies in solution by reagents, are in many cases de-
pendent on the employing of clean vessels. For in-
stance, a portion of water examined in glasses which
have been carelessly washed, may occasion a slight pre-
=vGoo(^lc
CLEANLINESS — GENERAL RULES. 21
eipitate with nitrate of silver or ehlodde of barium, and
thus seem to contain a chloride or a sulphate (403, 429),
when the cause of the precipitate maybe nothing more
than portions of salta adhering to the vessel.
"In the same manner the purity of an acid or a test,
is not unfreqnently affected by the state of the bottle
containing it, or by the dirty condition of glass rods
dipped into it, or of the funnels through which it has
been poured or filtered, or of the vessels used in its
transference ; and sometimes itia contaminated by laying
the stopper of the bottle containing it in a dirty place.
Nor is it only that kind of dirt or impurity which gives
an evident tinge to what it adheres to, that is to be
avoided, but ^ao numerous colorless substances, as
salts, solutions, &c, ; and in a word, anything which
differs from the principal substance itself, and is at the
same time liable to be dissolved or mixed with it.
" In consequence of these liabilities, and their inter-
ference with experiments, it should be established as a
general rule in the laboratoiy, that no apparatus, nor any
vessel (except such as may be destined to a particular
use, and is as convenient when with a little previously
adhering matter as if it were clean), be put away in a
dirty state. All vessels or instruments when resorted
to, should be found fit for the nicest experiment to which
they are applicable. Glass rods or stiiTcrs should be
preserved in a clean place ; glasses, on a clean shelf;
and stoppers, vphen taken out of bottles, should be laid
upon clean surfiicea. These attentions and regulations
will be found always useful, at times essential; and they
are generally more requisite and influential in minute
chemistry, than in large experiments."'
9. It is easy to clean even the dirtiest vessel, provided
it has not been allowed to remain long with the im-
purities adhering to it; this, indeed, should never be
permitted, and is readily avoided by making it a rule
never to leave work for the day until the whole of the
soiled apparatus has been thoroughly washed, and left
to drain during the night, ready for wiping the next
morning. For moat purposes of cleaning, water will
' Faraday's Clieinieal Manipulation, p. 523.
siGooi^le
22 CLEANING VESSELS.
be found sufficient^ especially when the dirt it still moist ;
and when mere rinsing does not remove it, gentle friction
with moist tow and coal ashes, will, in most cases, prove
effectual. When the form of the vessel to be cleaned is
such as will not allow the introduction of the hand (as
flasks, test-tubes, &c.), a piece of stick or wire, having a
little tow wrapped round the end, will be found veiy
convenient. Glasses or basins that have been set aside
to drain, should, before using, be wiped with a dry clean
cloth, to remove any adhering particles of dust or mois-
ture. Bottles or flasks, when recL'^ired to be perfectly
dry inside, may, afVer most of the water has been re-
moved, be easily dried by warming them gently, and
blowing air into them through a glass tube, either with
the belwws or from the lungs ; in tliis way the water is
converted into vapor, which is quickly removed by the
current of comparatively dry air.
"When a glass or dish ie gi'easy, it should be first
wiped as clean as possible wim tow or a diy cloth, then
moistened with a little strong potash, and, lastly, well
washed and rinsed with water. When the dirt to be
removed is resinous also, or tarry, the application of
strong potash or sulphuric acid will generally act upon
it in such a way, that subsequent washing with water,
together with gentle friction with coal ashes, will render
it quite ciean. It often happens, especially when a glass
has been allowed to dry in a dirty state, that an insoluble
crust is formed on the surface, which is very difhcult of
removal by mechanical means, but readily yields on the
application of a few drops of hydrochloric or some other
acid. An instance of this is afforded by solutions of
lime, which, on exposure to the air, frequently deposit
a crystalline sediment of carbonate of lime, which ad-
heres strongly to the glass, but instantly dissolves on
the addition of the acid,
10. When thrown upon his own resources, the student
will often find it of the utmost value to be able to sub-
stitute, in default of more perfect apparatus, the com-
mon things used in domestic life, which are to be found
in every house, such as glasses, plates, cups, saucepans,
&c. "V^hen in addition to these he has at his command
a bloivpipe, a small piece of platinum foil and wire, a
=vGoo(^lc
GENERAL R U L iD S. 23
flask or two, a funnel, and a little glass tubing of dif-
ferent sizes, lie will, witli the exercise of a little ingenu-
ity and contrivance, be able to go through a very con-
siderable course of experimentsJ chemistry. He may
rest assured that it is no disadvantage, but rather the
contrary, to be thus compelled to devise and construct
for himself rude and extemporaneous forms of appara-
tus; and if he should require encouragement to per-
severe in spite of the scantiness of his resources, he
need only be reminded that the majority of those whose
names shine brightest in the annals of science, have
laid the groundwork of their future eminence while
placed under the most unfavorable circumstances. So
it was with the great I)avy;' so with Dalton, with
Scheele, Taraday, Dumas, Liebig, and may others al-
most equally illustrious.
"Habits of coiTCCt and delicate manipulation veiy
much &cilitate experimental inquiries at all times. It
is not in difficult researches only that it is desirable, but
even in such common operations as testing for lime, or
iron, or sulphuric acid, its advantages become manifest ;
for either time is shortened, or the apparatus considered
as necessary is diminished, or effectual substitution is
made for those that may be wanting, and thus the ex-
periment becomes easy, where otherwise it would be
considered impossible. Besides facilitating such in-
quiries, it also diminishes the expense both in materials
and apparatus, and it produces beneficial habits in the
mind, by exercising it both in invention and percep-
tion even in this subordinate part of its operations.
'Nothing,' as Dr. Johnson observes, 'is to be considered
as a trifle, by which the mind is inured to caution, fore-
sight, and circumspection. The same skill, and often
the same degree of skill, is exerted in great and little
things.' "^
' "Hia means, of course, were very limited; not more extensive than
those with which Priestley and Scheele began their labors in the same
fruitful field. Hia apparatus, I belieye, consistedchiefly of phials, wine-
glasses, and tea-cups, tobacco-pipes, and earthen crucibles ; and his ma-
terials were chiefly the mineral acids and the alkalies, and some other
articles which are in commoo use in medicine," — Life of Sir H. Bavy,
by John Davy, M.D., yol. i, p. 43.
^ Farnday, op. pit. p. vi.
=vGoo(^lc
PNEUMATIC CHEMIST
CHAPTER n.
PKEUMA'CIC CHEMISTRY.
11. The gas-holder need in the following experi-
ments, which bears the name of its inventor, Mr. Pepys,
consists of an upright hollow box a, usually made of
zinc or copper, connectedby means of two tnbea b and
c, with a shallow pan d placed above it. The tubes are
open at both ends, the longer one c reaching to within
about half an inch of the bottom. The external glass
tube/ shows tliG height at which the liquid stands in
the vessel. The lateral opening e is closed by a screw-
eap before filling the vessel with water; the stopcoka h
and c are then opened, and water poured into the upper
pan, when it passes down the tube <?, the air escaping
up the other tube, until it is full, when no more bub-
bles of air will rise from the tube b.
When the gas-holder is filled with water, the stop-
cocks b and c are to be closed, and the screw-cap may be
=vGoo(^lc
PEEP All A'XION OF nYDHOGBN. 25
removed from e without danger of the water rushing
out, since it is kept in by the pressure of the external at-
mosphere ; but care must be taken not to remove the
screw-cap while either of the stopcocks is open, aa the
water would rush out with great force. The beak of
the retort may then be introduced, aa shown, in the
figure, when the gas will rise in bubbles through the
water, which is gradually displaced, and flows out
through the aperture e.'
Preparation of Hydrogen {p-)?
12. Weigh 300 grains of granulated zinc, and intro-
duce the fragments carefully through the tubulure of
the retort, sliding them, not
dropping them in, to avoid the ^'k- ^
risk of breaking the bottom of
the retort, which is usually of
thin glass, and eonsequentiy
seldom strong enough to bear
a blow without injury.
Pour upon the metal four
fluid ounces of dilute sulphuric
acid, consisting of one part hy
measure of oil of vitnol {S.0,80^, and five parts of
water.
Efiei'vescence immediately commences, owing to the
rapid evolution of the gas, the first portions of which,
being mixed with the common air previously in the re-
tort, may be collected separately in a small jar over the
pneumatic trough, and afterwards rejected.
The nature ot the decomposition that takes place may
be seen in the following equation :
' In the absenee of a gas-holder, the gases may be coiiected in jars
over the pneumatic trough (see par. 18).
' The specific gravity of hydrogen ie lower than that of any other
form of ponderable matter, being only 0'0G9, that of eommou air being
considered lOOO. 100 cubic inchca weigh, at the ordinary tempera-
ture and pressure of the air, 2"138 grains, while the same quantity of
common air weighs 31-00 grains. The atomic weight of hydrogen is 1,
and its combining volume \.
siGooi^le
Zn-{.HO,SO„=ZiiO,S03+lI.
The boak of the retort may now be inserted into the
lateral aperture of the gas-holder, which should have
been previously placed over the pneumatic trough so
as to catch the water as it is displaced by the gas
{Fig. 1).
when the effervescence subsides, and euffieiont gas is
collected, remove the gas-holder from the trough, and
proceed with the following experiments.
13. Place an inverted jar filled \Mth water, over the
tube b (Fig 1) and open both the stopcocks ; the gas
will immediately be forced up-
5'E-*- wards into the jar by the pres-
sure of the water in the pan
and in the tube c : close the
bottom of the jar with a plate
of glass, and remove it to the
pneumatic trough. Decant a
portion of this gaa to a smaller
jar (Fig. 3), and test its inflam-
mability with a taper. Ob-
serve the deposit of dew in the inside of the jar after
the combustion, which ia the water formed by the com-
bination of the hydrogen with oxygen, H -f 0—^0.
14. Fill a small jar with the gas, and having removed
it from the gas-holder, let it stand for a few seconds
with its open end upwards. If a liglited taper he now
=vGoo(^lc
PRliPARATION OF CARBONIC ACID, 2i
applied, no combustion will ensue, as the hydrogen will
have escaped upwards, on account of ite very low speci-
fic gravity.
15. Repeat the last experiment, holding the jar Vfith
the open end downward. On applying a lighted taper,
a slight explosion will take place, showing that the hy-
drogen had not escaped as before.
16. Transfer some of the gas from a large jar to a
small one, and from this
again to tubes, until it can ^ **'
he done without allowing U
any bubbles to escape m
When the gas ie to be de m ^
eant-ed into a jar oi tube ~=_ 3^ -~ ~ -^
which is much naiTowcr,
it may he fii'st translened ^^-S~- - ~
into a hpped glass ; oi in ^^^,1 ' - ^ ~
inverted funnel may be '-^=^^ — ~
used, as shown in Fig 5
17. Transferalittleofthehydiogcnmtln ■\^ i> lut ■ i
^adiiated tube, and mis it with varying but definite por-
tions of common air; then ascertain by experiment
what proportions detonate most loudly when a lighted
taper is applied. The jars used for these experiments
should be small and strong, to avoid risk of fracture by
the force of the explosion.
SECTION II.
Preparations of Carbonic Acid (00^).*
18. As this gas is to a considerable extent soluble in
water, it is better in its preparation not to use the gas-
holder, on account of the large quanity of water it would
then have to pass through, but to collect it at once in
jars over the pneumatic trough. (Fig. 6.)
19. Put 300 gi-ains of marble (CaO,COj) broken into
fragments about the size of a pea, into a retort, obseiv-
ing the same precautious as were recommended in the
' The Bpecifie gravity of carbonic acid is 1-524 (air being I'O), 100
cubic inclies weighing 47'26 grains. Its atomic weight is 22 ; and its
combining volume 1. At a temperatare of 60° water diaaolves about
its own bulk of eavbonle acid.
siGooi^le
R E 1* A R A T r
preparation of liydrogeii (12) MeTinre out in ounce
and a lialf of liydrochlo i d {H( 1) d lute t ith aa
equal quantity of wate t 1 po il e n \t e j on the
■^^rv„
marble The ga^ s n ed atel-y g ve ft causing
brisk eflervescenee, and it may be collected in jars
placed on the ehelf of the pneumatic trough, the firat
jai'ful being rejected as impure.
20. Introduce a lighted taper into a small jar of the
gas held with ilB open end upwards. It is instantly ex-
tmguished ; and as the carbonic acid remains some time
in me jar, on account of its high specifie gravity, the
taper may be extinguished repeatedly in the same jai-ful
of gas.
21. Pour a little lime-water (CaO) into a test glass
and thence into a jai- filled
Jfig. "■ with the gas, closing the
mouth of the jar with a
glass plate, and agitating
the gas and liquid together.
The lime-water almost im-
mediately becomes milky,
owing to the formation of
carbonate of lime(CaO,C02)
which is insoluble in water.
If a few drops of hydro-
chloric acid [HCl) be added,
the carbonate of lime is de-
=vGoo(^lc
EPARATION or CAKEONIC
29
composed, and iho milidiieaa disappears, cMoride of
calcium faeicg formed, which is aohihle in water.
{Ga.O,C0,+HOl^CaCl+RO+0O^).
22. Having filled a jar with the gas, pour it like water
into another jar somewhat
smaller (Fig. 8) ; this is easily '^' '
effected, owing to the high -^''^^'^
specific gi'avity of carbonic .^—^---^^^
acid. Test its presence in ^-IL^U/S ■ -#
both jars with lime-water (21), W
and by its power of extin- 1 1|
guishing a taper (20). /I3l
23. The high specific gra- -jit '^
vity of carbonic acid, and its ^A^®nO
power of extinguishing flame, \J
may be strikingly shown by
pouring it from a jar upon a lighted candle, which is
instantly put out.
24. By means of a narrow tube open at both ends.
fi!l a jar over the pneumatic trough, with air fi-om the
lungs. Test it with a lighted taper, and observe that it
causes an abundant precipitate in lime-water, owing to
the presence of carbonic acid (21).
25. Invert a jar filled with common air over alighted
taper floating on the water of the pneumatic trough
(Jig, 10) ; observe that it soon burns dim, and is shoruy
extinguished, the water at the same time slowly rising
=vGoo(^lc
30 I'REl'AEATION (
ISOXICE OF KiTBOGEN.
in tlic jar. The absoi-ption of air is
here owing to the disappearance of
the atmospheric oxygen, which com-
bines with the hydrogen and carbon
of the burning wax. Nearly one-fifth
of the air is thus condensed, that being
the proportion of oxygen contained in
the atmosphere ; the remaining four-
fifths are nitrogen. "When the com-
bustion is over, invert the jar, and test
the air contained in it with lime-water
tor carbonic acid (21).
SECTION III.
B-eparaiion of Btnoxide of Nilrogen (NOJ.'
26. Put 300 gi'aina of copper turnings into a retort,
and pour upon it an ounce and a half of strong nitric
acid {NO.} previously diluted with an equal quantity of
water. Decomposition immediately commences, and
the binoxide is formed by the action of the copper on a
portion of the nitric acid, thus : —
71 Cu+4A'0B=.1(C^O,ffO5)-i-N0j.
The gas which is first formed becomes orange, owing
to its conversion into nitrous acid (NOJ by combining
with the atmospheric oxygen contained in the retort
(NO,+2 0=N0.),
27. Transfer a little to a jar, and test it with a taper ;
obseiTe the orange fumes of niti-ous acid which are in-
stantly produced wherever the gas mixes with the air.
28. Measure a definite quantity of the gas in a gra-
duated I'eceiver, and transfer it to another jar over the
pneumatic trough : then measure off an equal volume
of atmospheric air, and add it by decantation, to the
binoxide. When the orange fumes have disappeared,
owing to the absoi-ption ot tlie nitrous acid by the
water, ti'Hiisfer it again to the graduated jar, and ob-
■ The specific gravity of binoxide of nitrogen is i'039, 100 culiio
inches weighing 32'22 grains. Its atomic weight is .'iO'O and ita com-
bining volume 2.
siGooi^le
PREPARATIOjM of 01. KFIAXT OAS. tSl
serve the volume of the mixture, Doticiiig accurately the
difference between thia and the sum of the onginal
volumes employed before mixing. Thia experiment
should be repeated three or four times, and if the re-
sults in each case agree pretty closely, take the average
of the experiments, and the amount of condensation,
divided by three, will give very neai'ly the quantity of
oxygen contained in the atmospheric air employed.
One equivalent of binoxide of nitrogen occupying two
volumes, when combined with two equivalents of oxygen
occupying one volume, forms one equivalent of nitrous
acid (NO J which is absorbed by the water ; consequently,
one-third of the gas absorbed consists of atmospheric
oxygen. If the experiment be carefully performed, the
absorption will be found to he equal to about one-fifth
of the volume' of common air employed, that being the
proportion of oxygen contained in it. (25).
Though the reaulta obtained in this way are not very
accurate, owing to the formation of other oxides of ni-
ti'ogen, they ai'o sufficiently so to allow of its occasional
employment in determining the quantity of free oxygen
in a gaseous mixture ; and also when the whole of the
■uncombiued oxygen has to be removed from a mixture
containing it.
SECTION IV.
Preparation of Olefiant Gan. (OA)-*
29. Pour into a retort six fluid drachms of alcohol
{CJ{^0,IIO) and add to it in small portions an ounce
and a half of strong sulphuric acid {SO,SO^, gently
agitating the mixture after each addition. Apply a mo-
derate heat, and take care that the black froth which is
formed towards the close of the operation does not boil
over. Collect the gas in jare over the pneumatic trough,
or in the gas-bolder.
80. Examine a small jarful with a taper, and observe
that, though the taper is extinguished, the gas burns
with a bright white flame.
' The specific gravity of defiant gas is 0'9SI, 100 cuWeincIies weigh-
ing 30-57 grains. Its atomic weight is 14, and its atomic volume 2.
=vGoo(^lc
32 PREPARATION OF CARBONIC OXIDE.
81. "When mixed with an equal volnnie of chlorine
(CI) the two ^ases combine, forming a heavy oily com-
pound, called chloride of olefiant gas [O^IZ^OQ.
The oil collects in drops on the sides of the jar and
on the surface of the water, while the gases are gradu-
ally absorbed.
Olefiant gas derives its name from the circumstance
of its forming this oily compound.
32. Mix together one volume of olefiant gas and two
volumes of chlorine ; close the jar with a glass valve,
and quickly remove it from the pneumatic trough. Ap-
ply a light to the mixed gases, and observe the dense
cloud of carbonaceous matter that is formed as the com-
bustion gradually passes down the jar, hydrochloric acid
being at the same time produced.
CjH,-|-4Cl=4H01+4G.
SECTION V.
Prtparaiimi of Carbmiie Oxide (CO).'
83. Carbonic oxide is prepared by the action of strong
sulphuric acid (^0,^0,) on oxalic acid (HO,C,03-|-2Aq).
"When a mixture of the two aeids is warmed, the oxalic
acid is resolved into carbonic acid, carbonic oxide, and
water, which latter unites with the sulphuric acid.
HOAOa-|-2Aq=00^+CO+3Ha
The carbonic oxide is purified from the carbonic acid
by passing it through a solution of potash or milk of
lime, .,
G0^+0O+K0=K0,C0i+0O.
34, Adapt a cork to a wide-mouthed bottle capable
of holding half a pint of water, and fit to it two tubes
(152), one of which, a (Fig. 11), should be about half an
inch in diameter, straight and sufficiently long to reach
nearly to the bottom; the other, 6, should only just
' The specific gtavity of carbonic oxide is 10'9tii, 100 cubic inches
weighing 30-21 grains. Its atomic weight is 14-0, and its atomic
=vGoo(^lc
PREPAKATION OF CARBOMIC OXIDE.
33
pierce through the cork, and should ho betit so aa to
deliver the gaa, as shown in the figure : the diameter of
this tube need not he more than about ^ of an inch.
The beak of the retort may now be fitted with a cork,
which should be bored to allow the bent tube e to pass
through it ; and care must be taken that this tube is
sufliciently small to slide easily down the tube a, and
long enough to reach to the bottom of the bottle.
!Four ounces of a tolerably strong solution of potash
(KO) may now l)e introduced into the bottle.
35. Charge the retort with 180 grains of ciystalHzed
oxalic acid (HOjCjOj+SAq) and two fluid ounces of
strong sulphuric acid (^HO,SOg'). On applying a gentle
heat, the gas is given off, the first portions of which
must be rejected as impure, and then two or three jars-
fal may be collected over the pneumatic trough before
the bottle containing the potash is connected with the
retort. The gas thus obtamed is a mixture of carbonic
acid and carbonic oxide (83).
36. Having collected two or three jare full of the
mixed gases for comparison, adapt the bent tube c to
the mouth of the retort, and proceeded to purify the
gas from carbonic acid, by passing it through the alka-
hae solution in the bottle. Pure carbonic oxide may
then be collected.
37. Agitate a little lime-water with a jar full of the
Tinpurified gas ; the presence of carbonic acid is shown
by the formation of carbonate of lime (21).
=vGoo(^lc
34
ION 01' OXYGEN
88. Repeat the experiment with ajar full of the puri-
fied gas. No precipitate ought now to appear.
39. Apply a Hghted taper to ajar full of the impure
gas, and observe the characterietic pale blue flame with
which the earbonic oxide bums.
40. Do the same with a jar of the pure gas : the flame
ia brighter than when carbonic acid was present.
41. Pour a little lime-water into the jar need in the
last experiment immediately after the combustion of the
gas. The white precipitate which now appears, and
which was not formed when the same gas was tested
previous to the combustion, shows the result of that
process to have been the formation of carbonic acid
00+0=00^.
SECTION VI.
Preparation of Oj:yijen C^}.*^
42. Adapt a bent tube of the form sho^vn in the
figure, to a small hard glass flask, by means of a per-
forated cork.
Then weigh ] 00 grains of dried chlorate of potash
(K0,C10,,), mix it with 20 grains of black oxide ot
manganese (MnOj), and place the mixture in the flask ;
' The Bpeeific gravity of oxjgen is 11057, 100 ouliicinelics weighing
34-29 grains. Its atomic weight is 8, and its combining volume J.
=vGoo(^lc
PIlBPAllATION OF OXYGEN. ^5
adjust the tube so aa to deliver the gaa into the gas-
holder, or under the shelf of the pneumatic trough
(Fig. 12), and apply the heat of a lamp.
The chlorate of potash is thus decomposed, and gra-
dually gives off the whole of its oxygen, which passes
out through the tube, and may be collected either in the
gas-holder or in jars, while chloride of potassium (KOI)
remains in the flask, together with the oxide of man-
ganese, which is not decomposed during the process.'
]IO,aOs=KC!+60.
The first portions of the gas should be rejected as
impure, being mixed with the common air contained in
the flask and tube.
43. The jara used for the following experiments
should be open both at the top and
bottom, the edges of bothbeing ground ^'s-^'-
smooth, so as to be closed air-tight
with a glass valve 6 (Fig. 13).
44. Fill a jar with the gas, and in-
troduce a glowing taper; it will in-
stantly burst into flame, and burn with
great brilliancy, until moat of the oxy-
gen is exhausted by combining with
Sie carbon and hydrogen of the wax.
45. Introduce into another jar of
the gas a email piece of ignited char-
coal, attached to the end of a wire. It bursts into vivid
combustion combining with the oxygen, and forming
carbonic acid (co^), the presence of which may be proved
by agitating a little lime-water in the jar (21).
46. Repeat the experiment with a small coil of th.in
iron wire, to whieh a little charcoal or amadou should
be attached and ignited, for the pui^oae of heatingthe
iron sufficiently to cause it to burn. The iron combines
with the oxygen, forming the black oxide (FcgOJ, fused
globules of which drop to the bottom, and should be
received in water, as they are so intensely hot as to
fuse into the glaze of a plate if allowed to fall upon it.
' The oside of raangaaeso is here used, becaase it is found that,
■when thus mixed, chlorate of potash gives off its osvgen with much
greater (kfiility and at a lower temperature than when heated alone.
siGooi^le
PR EPA BAT ION OE SOLUBLE GASES,
47. Place a fragmeJit of sulphur
about the size of a pea iu the de-
flagrating spoon, set it ou fire by
holding it over a lamp, and in-
troduce it into a jar of the gas ;
the sulphur burns with a brilliant
blue flame, combining with the oxy-
gen, and forming suiphuroue acid
(^ )
48 Mix together two volumes of
hydrogen and one of oxygen, and
■H ith the mixture fill a small jar or
tube which for this experiment
should be made of thick glass. On
ippl>ing a light, the gases combine
■with a loud explosion, forming
water. ii+o=-ffO.
SECTION vtl.
Preparation of Gases which are soluble in Wafer.
49. Although in the preparation of many of the com-
mon gases it is most covenient to collect thera over
water, either in the gas-holder, or in jars placed in the
pneumatic trough, still there are many cases in which
this method is inapplicable, as when the gas is to any
considerable eictent soluble in water. It is usual in such
cases, especially when gi'eat purity is necessary, to col-
lect them in tubes or jars over mercury, which is not
acted upon by the majority of the gases. For common
pui'poses, however, some of them may be collected by
the displacement of common air in dry bottles, and the
more the gas differs in density from atmospheric air,
the more ia this method applicable.
Hydrochloric acid gas and ammonia may be taken as
examples of the process.
Preparation of Mydroeldoric acid Gas (H01).i
50. This gas is easily obtained by the action of sul-
phuric acid on common salt.
' The specific gvavity of hydrochloric ncid gas la 1-269, 100 cubic
inches weighing HB-ai grains. Its atmyiic wejj;lit is ST'O, and its aloiiiic
=vGoo(^lc
PREPARATION OP HYDROCHLORIC ACID GAS. 37
To the beak of a retort, a bent tube of tlie forni repre-
sented in Fig. 15, is adapted by means of a perforated
cork; a loose roll of filtering paper is introduced into
the neek, to retain any moisture that may distil over ;
and the retort is charged by introducing 300 grains of
dry chloride of sodium (NaCl), and adding to it six
fluid drachms of strong sulphuric acid {110,80^). Im-
mediate effervescence takes place, and the beut tube ia
passed into a dry bottle of about a pint capacity, which
should be furnished with a greased stopper ; while the
bottle is filling, the mouth may be loosely closed with
a piece of card or paper.
Observe the dense fumes which are formed wherever
the gas mixes with the air, especially if the atmosphere
is damp, owing to the combination of the gas witii the
aqueous vapor. The bottle maybe considered full when
the gas has been flowing over from the mouth of the
bottle for two or three minutes ; the tube should then
be cautiously withdrawn, and the bottle tightly closed
with the stopper. Three or four bottles may be simi-
larly filled with the gas, a gentle heat being applied if
necessary.
The decomposition may be thus represented : —
NaCI+HO,S(?3=NaO,S03+HC!,
The sulphate of soda of course remains in the retort.
51. Ascertain the action of the gas on a lighted taper.
52. Remove the stopper from one of the bottles, in-
=vGoo(^lc
-^8 PfiKl'ARATION OF AMMONIAC Al, HAS.
Btaiitly close it again vvitli a diy glass plate (apreeautiou
which is on no aceonnt to be omitted, aa the stopper
might in that case become immovably fixed), and plunge
it with the mouth downwards into the water of the
pneumatic trough. If the bottle has been well filled,
the water will, when the glass plate is removed, quickly
raise and nearly fill it, while the unabsorbed residue
shows the quantity of common air left in the bottle.'
This experiment must not be made without first re-
moving the stopper, and substituting the glass plate ; if
it is attempted to take out the stopper while the bottle
is under water, there is great danger of its becoming so
fii-mly fixed, as to be almost incapable of removal, owing
to the absorption of the gas by the water, and the foi--
mation of a partial vacuum.
53. Test a little of the acid solution obtained in the
last experiment, in a tube, with litmus paper, and after-
wards with a few drops of solution of nitrate of silver
{AgO,NO^. The white precipitate, which is chloride of
silver (AgCl), will be found to be insoluble in nitric
aeid, but readily soluble in ammonia (429).
54. Reserve a bottle of the gas for an experiment
(60) with ammonia.
SECTION VIIL
Preparation of Ainmoniacal Gas (NKj).^
55. This gas may be prepared in a similar manner to
the last ; but as it is specifically lighter than common
air, the bottles in which it is collected must be kept,
while filling, with the mouth downwards, the deliver-
ing tube passing upwai-ds, to the top ( J'ig. 16) ; the
neck of the retort should be furnished as before with a
roll of filtering paper.
56. Reduce 300 grains of quick lime (CaO) to powder
in a mortar, and slake it in a small basin with a di'achm
' Water at common temperatures iscapable of dissolving no leas than
480 times ita own volume of hjdrocMorie acid. The liquid hydro-
elilorio or muriatic acid of commerce la a solution of thegaain water.
' The specific gravity of ammoniacal gas is 0*589, 100 cubic inches
weighing 18'288 grains, Its atomic weight is 17, and its atomic
=vGoo(^lc
PKEPAEATION
iMMOHIAOAL
and a half of water ; then pound 400 grains of muriate
of ammonia (I^^Cl) ; mix the powders aa quickly aa
possible, and without loss of time transfer the mixture
to the retort. The following decomposition takes
place : —
NII,C14-CaO=CaCl+jrO+NH3.
If the gas does not come over rapidly, a gentle heat
may be applied. "When three or four bottles have been
filled, proceed with the following ex-
periments : — ^'^' "■
57. Obsei've the effect of the gas on a
lighted taper : it extinguishes the flame,
and at the same time shows a slight
tendency to bum with a pale gieen
flame.
58. Tiemove the stopper from one of
the bottles, and close the mouth with a
dry glass plate (read paragraph 52} , then
invert it, and having placed it under
water, remove the glass plate and ob-
serve the rapid absorption. That which
remains unabsorbed is atmospheiic an.'
59. Test the liquid obtained in the
last experiment (which is a weak solu-
tion of ammonia) with turmeric and led-
' Water at common temperatuveg is cipil Ip oi ibauiliii
times ita volume of ammoiiiacal gas.
ear!) ^00
=vGoo(^lc
40
DISTILLATION.
dened, litmos-papGr ; the first is turned brown, the latter
has the blue color restored.
60. Remove the stopper from a bottle of the gas, and
also from the reserved bottle of hydrochloric aeid (54),
replacing them with dry glass plates. Then invert the
latter over the bottle of ammonia (Fig. 17), and cau-
tiously remove the glass plates so as to allow the gases
to mix. Dense white fumes, consisting of muriate of
ammonia (NH^Cl) are immediately produced, which in
a ehort time collect in flakes, and fall like snow on the
sides and bottom of the vessels. In this combination of
the hydrochloric aeid with the ammonia, considerable
heat is evolved.
CHAPTER m.
DISTILLATION.
Distillation of Water.
61, Adapt a cork to the neck of a quilled receiver,
and bore a hole through it to fit the neck of the retort,
which should pass through it for about two inches.
When this is done, the apparatus may be fitted up as
shown in the figure (Fig. 18). The funnel which snp-
=vGoo(^lc
distillation: of watbr, 41
plies water for cooling the neck of the retort, has its
throat partially obstructed by a plug of tow, to regu-
late the flow of liquid ; the neck of the retort Is covered
by a slip of bibulous paper of the form of
the annexed sketch (Fig. 19), cut of such Kg- lo-
a width as almost completely to encircle '
the neck; and between the lower end of
the paper and the quill receiver a thin
fillet of tow is twisted tightly round the
glass, to cany off the superfluous water,
which drops into a basin placed underneath
for its reception. The quill of the receiver
liaseea into a small flask or bottle, which is
kept immei-sed in water duiing the process,
in order to keep it cool.
62. When the apparatus ie thus arranged,
the retoi-t must be cautiously chai'ged with common
water till nearly half full, cai-e being taken that none
of it gets into the neek, as it would run down into the
receiver and contaminate the distilled water, which
should otherwise be pure. The upper part of the body
of the retoi-t being tlien covered with a conical cap of
paper to prevent loss of heat by currents of air and
radiation, the lamp may be applied, care being taken
that the ebullition does not go on too violently ,lest any
of the impure water should splash or boil over into the
neck of the retort. If, instead of boiling quietly and
uniformly, the water in the retort "bumps," owing to
the sudden disengagement of large bubbles of steam, a
few fragments of broken glass or
platinum wire may be placed in ^'^- ^°-
the retort to assist the formation
of small bubbles ffom their sur-
face. The first ounce of water
that comes over should be re-
jected as impure, after which
two or three ounces may be dis-
tilled for examination.
63. While the distillation is
going on, another portion of the
water operated on may he tested, witli the view of die
=vGoo(^lc
42 DISTILLATION.
covering eom e of the impurities present in it. Fill four
teat-tubes about one-thii'd full of the undistilled water,
and add to them respectively a few drops of tlie follow-
ing reagents.
(a.) To the first add a solution of chloride of barium
(BaOl) ; a white precipitate, insoluble in nitric acid,*
indicates the presence of sulphates (403), most com-
monly sulphate of lime {OaOfSO,).
(b.) To another portion add a solution of nitrate of
silver {AgO,NO^. If any chloride is present, usually
chloride of sodium (JVaCi), a white curdy precipitate of
chloride of silver (AgCl) will bo produced, insoluble in
nitric acid, but readily soluble in ammonia (429). By
exposure to the light this precipitate gradually becomes
purple, especially when the water contains organic
matter.
(c.) To the third tube add a little lime-water {CaO in
water) : a white precipitate, soluble in nitric acid, shows
that carbonic acid {CO^) is present (420).
(d.) To the remaining tube 03;atoeo/amm(mia(iVff,O,
CjOj) may be added, whieh will give a white preeipitato
if any lime is present (218).
64. Test the distilled water in the same way; if pure
it will of course furnish no precipitate with any of the
65. Evaporate a few drops both of the distilled and
undistilled water on platinum foil or a clean slip of
glass: a considerable residue will probably be left by
the latter, but no trace of solid matter ought to be ob-
servable where the other lay.
66. During ebullition, the water in the retort usually
becomes turbid, owing to the formation of a white in-
soluble powder, which may be separated by filtration
when the distillation is over.
To prepare a filter, take a small piece of white filter-
ing or blotting paper, and fold it twice from side to side
(Fig. 21); then round off with scissors the projecting
corners, so that the paper may fall wholly within the
' Ivi testing the solubility of a precipitate in any liquid, pour off a
small portion into a separate tnlie for the experiment, reserving the rest
for comparison.
=vGoo(^lc
DISTILLATION OT IVATEB. 43
funnel (Fig. 22), Moisten tlie paper placed in a funnel
with distilled water, and then carefully pour in the H-
q^uid to be filtered, usma i gli ■* i >d to conduct it
(Fia;. 23), (636).
When moat of the liquid has passed through, the
white powder may be detached with a knife from the
paper, and introduced into i test tube the cleai' solu-
tion being reserved for examination (68)
67. (a.) Add a few diopa of dilute mtnc acid to the
powder in the tube, and obierve thit it dib&olves with
effervescence, indicating that it is a caibonate (419).
(6.) Supersaturate the solution thus obtained with
ammonia, and add a little oxalate of ammonia {NHtO,
0^0^ : a white precipitate shows the piesence of lime
(218). The powder is thus proved to be carbonate of
lime (CaOjCOJ. This carbonate of lime had been held
in solution by the excess of carbonic acid contained in
=vGoo(^lc
44 DISTILLATION OF HYDROCHLORIC ACID.
tJie water; when the gas is expelled duriug ebullition,
the carbonate is precipitated.
68. Test the solution filtered from the carbonate ot
lime in (66) with chloride of barium, nitrate of silver, Um^
water, and oxalate of ammonia; and compare the results
with those obtained in (68), when the water wae ex-
amined in its natural state. As most of the lime has
been separated as carbonate, we may expect to find less
of it in solution than before, but more of the sulphates
and chlorides, since they still remain dissolved in a more
concentrated form.
Distillaiion of Liq^iid HydrocMorie Acid (HCl in water).
69. Fit up the appai-atus as in the ordinary process
of distilling water (61), taking care that all the joints ai'e
perfectly tight: then remove the retort, and introduce
through the tubulure 1000 grains' of diy chloride of
sodium (NaCI) in coarse powder, taking care that none
of the particles fall into the neck of the retort ; then
adjust tlie apparatus as before. Measure into the small
flask or bottle which is to receive the distilled acid, 12
fluid drachms of water, and mark with a file or a strip
of waxed paper, the height at which it stands ; and
having emptied it, measure into it seven drachms of
distilled water. During the distillation care must be
taken that the quill of the receiver dips under the sur-
face of this water, which will assist in condensing the
acid fumes, some of which might otherwise escape.
Into a small evapoi'ating basin, pour seven drachms
of water, and add gradually to it six di'achms of strong
sulphuric acid {HO,SO^, stinnng the mixture with a
glass i-od. When nearly cool, this dilute acid may be
poured cai-efally into the retort through a email funnel,
avoiding any splashing or soiling of the neck. A gentle
heat may then be applied, which must be regulated ae-
' III this and many of tlie other experiiaents, small quantities we
mentioned to suit the conyenience of my class of Practical Chemistry,
the leaaoiia being only two hours long. When the prodocts of the ex-
periments are wanted for nse, much larger ciuantities mast frequently
bt! employed-
siGooi^le
DISTILLATION OF AMJIOXIA. 45
cording to the rapidity with which tlie acid distils over,
great care being taken tliat the mixture does not boil
over into the neck of the retort (60).
The distillation may be continued until twelve
drachms of acid have come over, which may be known
by the mark previously made in the receiving flask.
70, The acid in the receiver may now be examined
as to its purity. Pour a little into a test-tube, dilute it
with about three times its bulk of water, and add a few
drops of a solution of chloride of barium ,- if a white pre-
cipitate appears which is insoluble in the acid, it shows
the presence of sulphuric acid as an impurity (403^.
71. Evaporate a few drops of the acid on platinum
foil or a clean slip of glass : no trace of the spot where it
lay ought to remain. Any solid residue shows the
presence of some saline impurity, caused probably by a
little of the salt employed having got into the neck of
the retort, and been washed down into the receiver.
SECTION III.
Distillation of Liquid Ammonia (MHs in water).
72. Prepare the apparatus as in the distillation of
hydrochloric acid (69).
Pound 450 grains of quick-lime (CaO), introduce it
into the retort through the tubulure, and pour gradually
upon it two ounces of distilled water. Measure into
the receiving flask or bottle fifteen drachms of water,
and mark with a file or waxed paper the height at which
it stands; empty it, and pour in two drachms of distilled
water for the quill of the receiver to dip intoduringthe
distillation.
"Weigh out 530 grains of muriate of ammonia (Nlt^
CI), dissolve it iu three ounces of water in a small eva-
porating basin, and pour the solution into the retort.
The distillation may now be commenced, carefully
regulating the heat, and continuing it until the distilled
liquid reaches up to the file mark in the receiver, when
15 drachms will have been collected.
CaO +iVfl4CT=NH^HO+ Ca CI
=vGoo(^lc
46 DISTILLATION Oi" LIQUID NITRIC ACID.
73. Pour a little of the ammoiiiaeal solution thus
prepared into a test-tube, and add to it a few drops of
chloride of barium : if a precipitate appears, it is owing
to the presence either of carbonic or sulphnrie acid. To
distinguish between them, add nitrio acid in slight ex-
cess ; if the precipitate thereupon dissolves, it is carbonic
acid (421) ; if not, it is sulphuric (403).
74. Test another portion of the ammoniacal solution
with a little oxalate of ammonia ; if a white precipitate
is formed, it is owing to the presence of lime as an im-
purity (218).
75. Supersaturate a little of the distilled liquid with
nitric acid in a test-tube, and add a few drops of a solu-
tion of nitrate of silver (AgO,NO^ ; a white precipitate
indicates the presence of hydrochloric acid or a chloride.
If a further portion of the ammoniacal solution be
added, 80 as to render the liquid alkaline, the precipi-
tate redissolvea (429). ,
76. If no precipitate occur with any of these teats,
evaporate a few drops of the ammoniacal solution on a
Blip of glass or platinum foil, and obseiTe whether any
trace of saline impurity is left.
SECTION IV.
DhtiUatton of Liguid N'itric Acid (N ?j in water).
77. Fit up the apparatus as in the distillation of hy-
drochloric acid (69). Introduce into the retort 1000
grains of nitrate of potash (£0,^0,) ; pour upon it ten
drachms of strong sulphuric acid {ffO,SOg) previously
diluted with an equal bulk of water, and apply a gentle
heat, observing the same precautions as were recom-
mended in the former cases (61, 69).
KO,N05+2(ifO,S03)=KO,S03,HO,S03-|-HO,H05.
78. While the distillation is going on, dissolve a few
crystals of the nitrate of potash in distilled water, for
the purjiose of ascertaining its purity,
(a.) Test a little of the solution with nitrate of silver
{AgOflfO^); if any chloride is present, a white curdy
precipitate appears, which is insoluble in nitric acid,
but readily soluble in ammonia (429).
=vGoo(^lc
DISTILLATION 01' LIQUID NITRIC ACID. 47
If the nitrate employed is contaminated with any
chloride, the acid that distils over is sure to contain a
little hydrochloric acid [HOI).
(6.) To another portion, add a solution of chloride of
barium {BaOl) ; if any sulphates are present, a white
precipitate is produced, which is insoluble in nitric
acid (403).
79. Dissolve a small quantity of nitrate of potash in
hot water, in an evaporating basin, adding the salt as
long as it is taken up by the water on stirring ; pour the
hot solution into another basin, and obaerve the gradual
formation of crystals as it cools. Eemovc some of these
from the liquid, and drv them on filtering paper ; then
vedissolve them in distilled
water, and test the solution "^'
as before, with nitrate of
silver and chloride of barium.
The precipitates, if anj',
will be less dense than m
the previons examination,
showing that a partial puri-
fication has been effected,
■ 80. The distilled nitric
. acid may now he tested for
impm-ities, bnt before the
test liquids are applied a
portion should be diluted with four oi five times its
bulk of distilled water, since the chlonde of barium is
itself insoluble in strong nitric acid, and would conse-
quently cause a precipitate, even though no sulphuric
acid were present. A portion may then be tested for
sulphates and chlorides with chloride of barium and
nitrate of silver (403, 429).
81. If the distilled acid is found to contain sulphuric
or hydrochloric acids, it may be purified from them by
adding a solution of niti-ate of silver as long as any pre-
cipitate is produced, and re-diatilling ; when those
acids will remain behind in combination with the oxide
of silver.
HGl+EO,SOi+2{AgO,N'Oi]=A.gO\+AgO,SO,+2{liO,NOt,).
=vGoo(^lc
GLASS WORKING.
CHAPTER IV.
GLASS-WOEKING.
82. TiiK most convenient form of apparatus for work-
ing glass on the small scale, is the water blowpipe,
which consists of an upright box, about fifteen inches
high, of the form represented, in Figure 25. It is usually
made of zinc or copper, and is divided into two com-
partments by the plate «, which passes down to within
about half an inch of the bottom, thus leaving a com-
munication open between
P'E ^'^- the two. The lower end of
the tube h is closed by a
valve opening outwards, to
prevent the escape of air in
that direction : thebox should
be filled about half full of
water, and when used, air
is blown through the tube
h. The pressure thus oc-
casioned in the compart-
ment c, forces a portion of
,^^j ^jj, ^ ^ the water into the next divi-
sion d, where it rises to a
higher level than m c, and by its superior pressure forces
a stieam of an thiough the fine aperture at the extre-
mity of the tube e, as long as it continues to stand at a
higher level than in c. ui this way a continuous jet is
readily obtained, with much less fatigue to the operator
than with the raouth blowpipe.
83. If the blowpipe flame be examined, it will he
found to consist of two distinct parts, which may be
called, for the sake of distinction, the inner a, and the
outer flame 5 (Fig. 26}. The blue point of the inner
flame is evidently surrounded on all sides by the burn-
ing gas, no atmospheric oxygen being near it, so that
any substance containing oxygen loosely combined,
=vGoo(^lc
GLASS-WORJiINO,
placed in it, will be decomposed by the powerful de-
oxidizing affinities of the carbon and hydrogen of the
coinhuatible sases : on this aceou!it the inner flame is
usually called the deoxidizing or reducing flame. The
outer flame, on the contrary, is surrounded on all sides
by the external air, so that here there is no excess of
combustible or deoxidizing matter, but rather an excess
of atmospheric oxygen ; so that an oxidized substance
may be placed at its extremity without danger of de-
oxidation, unless such decomposition is eflected by the
mere heat of the flame, independent of its chemical
action ; on the other hand, most substances, having an
affinity for oxygen, placed within its influence, be-
come oxidized at high tempera-
tures, and hence it is usually called ^'^^ ^■
the o.TwiiZino' flame.
84. The English flint glass, of -
which the tubes and rods com-
monly in use are made, contains
in its composition a quantity of
oxide of lead (PbO), which, when
heatediueontactwith deoxidizing
matter, is vei^ easily decomposed. mon-pipc Eiam? .
On this account it is necessary, in
heating glass with the blowpipe, to take care that it
does not approach the deoxidizing flame, but is kept at
the extremity of the oxidizing flame, otherwise a black
stain of metallic lead will be deposited on the surface
of the glass. Slight stains of this description may
generally be removed by holding the glass for a few
seconds in the oxidizing flame ; this convei'ts the lead
again into oxide, which dissolves in tlie glass.
85. Make a few glass stirring rods, of lengths varying
from five to eight inches. To do this, a piece of solid rod,
long enough to make two stirrers, should be held at a
short distance fromthe extremity of the flame, andgradu-
ally brought towards it ; a rotating motion being com-
municated to it by means of the finger and thumb,
so that the part where the heat is applied may be uni-
formly heated all round (Fig 27). "When the glass
=vGoo(^lc
50 G L A S S - IV E li I N G.
begins to soften, it should be gently jmlled with both
liaiids, until it assumes the
^^'s- 2v. form represented in Figure
28, when it may be re-
moved from the flame ;
and Laving been scratched
with a file across its nar-
rowest part, is gently
broken asunder (Fig. 29).
The sharp edges are then
held in the flame until they
areroundanduniform(Fig.
30) ; after which the other
end may be worked in the
same way, only making it
rather more tapering and
pointed,
86. tfoin together two rods
of equal d a i t 1 i tliis purpose, take two short
pieces of rod, the ci.tiemities of which are smooth and
flat, and hold the ends which are to be united in the
blowpipe flame until partial fusion takes place. Then
with a steady hand bring them together, observing that
the edges of both coincide, and press them gently, so
as to cause them to cohere perfectly together. Keep
the newly-fonned joint in the flame for some minutes,
taming it constantly round, and altei'nately pulling and
pushing, in order to weld the two pieces firmly together.
=vGoo(^lc
iVOKKING.
When tliis is properly done, the rod is ns strong at tJie
junction as in any otlier part, "but a slight inequality will
always be visible, however neatly the operation
may have been performed. ^^'^^^
87. Make a specific-gravity glass oi ih.e funn and
size shown in Fig. 31 (149).
88. Make a small syphon tube. Take u piece
of tubing ten or twelve inches long, and a fourth
or 3, third of an inch in diameter, and hold it
diagonally in the flame of a gas or apirit-lamp,
turning it constantly round, and by gently mov-
ing it up and down in the flame, heating two or
three inches of the central part of t!ie tube.
When the glass begins to soften, apply a gentle
pressure with both hands, so as to bend it slowly,
and continue to do so until it has assumed the
form shown in Fig. 32. If the tube is too strongly
heated, or if the pressure be too strongly and
suddenly applied, uie bend, instead of bemg rouu
uniform, will be abrupt and wrinkled, in
which case it is very hable to ci-ack, either ^'k-
spontaneously, or when exposed to alight
variations of temperature. The extremi-
ties of the tube must now be rounded off
by being heated to redness for a moment
in the flame of the blowpipe. When the
glass operated on is at all thick, or of an
unequal form, some care is necessary in
annealing, or gradually cooling it ; this
may be eflected by removing it slowly
from the flame, and then laying it across
a piece of tube, so that the hot part does
not touch any cold substance, and cover- gy^hon tuio.
ing it loosely with paper, to prevent too
rapid cooling by radiation.
89. Make a few test-tubes. Apiece of tube may be
taken about half or five-eighths of an inch in diameter,
and eight or ten inches long, which will serve for two
test-tubes.
The central portion must be heated in the manner de-
scribed for heating glass rod (85), and gradually drawn
out, the tube being constantly turned round, when it
=vGoo(^lc
52 G L A S S - W K K r K «.
will assume the form shown in Ftg. 33. The heat
should now he applied to the part of the tube marked
a, and the other piece gradually drawn out, eare being
taken not to fuse the tliin thread of glass that ie foi-med.
and which connects the two parts of the tube (Fig. 34),
until the base of the tube has become round and uni-
form ; when this is the ease, and the connecting thread
has become very thin, the heat may be applied to the
point where it joins the tube, when it will instantly fuse
and separate, leaving the tube in an almost finished
state. There will generally be found at the bottom of
the tube, however, a small lump, more or less distinct,
formed by a portion of the thread having fused into it;
to remove this, again heat the round end red-hot for a
short time, until the lump disappears. On re-
moving the tube from the flame, blow air gCTjJly
into it, for the purpose of swelling out the bot-
tom to its previous round form (Fig. 35), as it
usually collapses and flattens while in a state of
fusion.
90. The other portion of the tube may now be
finished in a similar way, by applying heat to the point
J, and drawing off the irregulai' termination until the
thread of glass is sufficiently a,ttenuated to be removed.
When it is required to make a test-tube of a piece of
tubing only long enough for one, all that is necessary
is to melt on to one end another piece of waste tubing
or rod, to serve as a handle, after which the end may be
drawn off, as in the former case.
91. To complete the tube, the open end must he
spread out a little, as shown in Fig. 36, so as to form a
kind of border. This is done by softening the end in
the blowpipe flame, and then, by means of a thick iron
=vGoo(^lc
G L A S S - W K K I S G . 53
wire, 01" the smooth end of a file (which should be pre-
viously heated by being held in the flame), introduced
and carried round the ^.^ ^^
opening, the
is uniformly ]
outwards.
92. Cement together
two tubes of equal dia-
meter. Thia is done
in a similar manner
to that already de-
scribed in the ease of
rods (86). It reqiiires,
however, more care
and dexterity to maintain the tube of nearly uniform
thickness at the point of junction, as it is liable to col-
lapse and become irregular in form. When it does so,
one end of the tube should be stopped up with a bit of
cork or by hermetically sealing, and while the junction
is in a state of semi-fusion, air
should be gently blown into the
tube : in thia way it may be
brought again into a proper
form. "When the glass is thin,
the edges which are to be iinited may be spread out a
little, as shown in Fig. 37, by means of a heated wire
or file (91), when the joint will be stronger than it would
othei-wise be.
93' Cement together two tubes of unequal diameter.
When it is required to join a narrow tube to a wider
one, it is necessary to draw out the latter in the blow-
pipe flame until a portion of it is contracted to the dia-
meter of the former (85) ; tlien with a file it is divided
at that point of equal diameter, and cemented to the
smaller tube in the same way as in the previous ease.
Sometimes, when the glass is thin, it is advisable to
■widen the extremity of -the smaller tube, so as to over-
lap the other (Fig. 38), which is readily done by means
of an iron wire (91).
In this operation, it is always advisable to maintain
the junction in the flame for some little time, to allow of
=vGoo(^lc
54
SS- WORKING.
the complete amalgamation of the two portions of glass ;
and as the tendency to collapse is greater the longer it
is fused, it will generally be found necessary to
blow it out slightly, as recommended in (92).
In this way, some small fannela may be made
(Fig. 39).
94. Prepare tubes for a washing bottle. The
tubes required for this purpose are of the form
shown in Fig. 40, the upper end of the longer
'^tX!' one being drawn out so as to leave only a small
aperture.
"When the bottle is prepared and filled with water, a
small stream of water may he forced
through this tube by blowing air down
the bliorter one ; it is of gi-eat service
m -^^ T,shing precipitates on a filter, and
loi mmy odier purposes (169).
95 Prepare tubes for a sulphuretted
hifdrog&n {hydrosulphurio acid) appara-
tus The form of apparatus used for
generating hydroeulphnrie acid, and
passmg it into water or saline solu-
tions, IS represented in Fig. 41 (699).
The finer tubes, d and /, may usnally
be bent in the naked flame (88), the
extiemities being afterwards slightly
fused V, ith the blowpipe in order to round off the sharp
edges ; and care must be taken that the wider tube e is
of sufficient calibre to admit of the tube if passing freely
down it.
96. Attach a narrow tube at right angles to a wider one.
Heat the wider tube to redness at the point where the
junction is to be made ; and by means of a bit of waste
rod or tubing c (Fig, 42), draw it out, when it will assume
the form represented in the figure : then with a sharp
file remove the portion e at the point h, and fuse to the
=vGoo(^lc
GLASS- WORKING. 55
projecting piece thus left the smaller tube, in the
manner described in ('
Sulyhurettod Hydrosen Appa
97. Blow some small bulbs. "When it is required to
blow a bulb at the end of a tube, the extremity should
be closed as in making a test-tube (89) ; if the glass is
tolerably thick, and the bulb
to be blown notlarge, all that ffs- m- ng. k.
is necessary is to heat the
end for about half an inch
as strongly as possible ; and ^^_
then, having removed it
from the flame, and holding
it horizontally in the hands
(Fig. 44), to blow air into
it until the pressure forces the softened glass to expand,
which it will do in the form
of a round bulb if the heat has
been properly applied, and the
tube be kept constantly turned
round while in the hands. This
latter precaution is absolutely
necessary, as the softened glass
would otherwise bend with its
own weight in one direction,
thus destroying the proper form
of the tube.
98. Seal a few tubes hermeti-
cally at both ends. This is an
operation of very frequent use in the laboratory, as it
=vGoo(^lc
56 G L A S S - \V R K I N G.
furnishes the most convenient and efficient means of
preserving Bmall specimens of many rai-e substances,
especially such as are volatile.
The tube is first sealed atone end, precisely as if it were
intended for a test-tube (89) ; the liquid or other
^'s- *=■ substance for which it is designed is then intro-
duced, as soon as the tube is quite cold, care being
taken that the upper part of the tube is not wetted
or soiled. The flame of tlie blowpipe is now
directed to the portion of the tube a little above
that intended for the sealed end, and when suffi-
ciently soft it is drawn out to a capillaiy tube, and
allowed to cool : it may aftei-wards be sealed by
fusing the lower part of the capillary tube a (Fig.
45), by momentary contact with the flame.
In this way seal a little sulphur in a tube without
melting or volatilizing any of it, the sulphur being
within an inch and a half oi' the upper end.
99. Seal some water hermetically in a tube. Having
sealed the tube at one end, while it is cooling take
another piece of tubing, which may be eight or nine
inches long, and a quarter of an inch in diameter, and
draw it out in the blowpipe flame ; then divide it in
the thin part by means of a file, when it will have the
form shown in Fig. 46 ; and when the sharp edges have
been rounded off in the blowpipe flame, may be used
as a pipette for introducing a little water into the sealed
tube without wetting its sides-
Then draw out the capillary neck (98), and when
cold seal it as before, leaving not more than the apace
of an inch between the upper end and the surface of
the water.
=vGoo(^lc
THE MOUTH B L IV P I P E.
CHAPTER V.
EXPERIMENTS WITH THE MOtlX'H BLOWPIPE.
100. BEEOEEproceediugto any blowpipe experiments,
it is necessaiy to acquire the knack of keeping up a
constant and unintermitting blast of air from the mouth,
as without this it is impossible to raise the heat to a
sufficient degree of intensity. The habit ia readily ac-
quired, and when once attained, the mouth and lungs
will be found to do their work almost mechanically,
without any sustained effort on the part of the operator.
101. The learner may first observe that on closing
the lips he can still without any difficult breathe
through the nostrils ; let him now distend the cheeks
with air from the lunga, and he will find that on closing
the communication between the mouth and throat he
can breathe through the nostrils for a length of time,
still keeping the dieeks distended. He may next in-
troduce the mouth-piece of the blowpipe between his
lips, and having putted out his cheeks with air from the
lungs, and again closed the communication between the
mouth and throat, let him breathe freely through the
nostrils, at the same time allowingthe distended cheeks
to force a cui-rent of air through the blowpipe. "When
the stock of air in the mouth is nearly exhausted, a
fresh supply is sent up from the lungs, when the cheeks,
again distended, will hy their elasticity keep up a cur-
rent of air through the blowpipe, while the operator
breathes through the nostrils as before.
The cheeks thus play the part of an elastic bag, with
a valve opening inwards, which, if connected with the
blowpipe, and distended with air, would force air
tlirough it as long as the tension of its strctohed sides
exerted sufficient pressure,
102. Seal a few tubes for the following experiments
(Fig. 47). The tubing employed fol" this purpose should
be about a quarter of an inch in diameter, and it may
be cut into pieces about five inches long, each of which
=vGoo(^lc
58
THE MOUTH BLOWPIPE.
will sei-ve for two tubes. The sealing should be effected
in the manner already described (89), and the same care
relative to the deoxidizing flameis neceasaiy, aa when the
water blowpipe is used (84).
Fig- 47, 10-3. Heat a small frag-
^. ... ,. ment of wood or paper in
a tube, and observe that it
blackens like all organic
substances.' This blacken-
ing or charring is owing to
the decomposition of the
lignine, which consists of
Cj^HijOio ; when exposed to
a high temperature the hy-
drogen, and oxygen, with
a portion of the carbon,
pass oft' in the form of acetic
or pyi'oligneous acid (ho.g^
li Oj) and tarry matter, with
other volatile compounds, leaving behind a carbonace-
ous residue. The acid character of the vapor may be
seen by introducing a strip of moistened litmus-paper
into the upper part of the tube while the decomposition
is goingon, when it will be speedily reddened.
104. Treat a fragment of horn {G^B.^,0„)y or isin-
glass (OgjHgjNjjOjj), similarly, in anomer tube :' observe
the character of tbe carbonaceous residue, and introduce
a bit of yellow turmeric paper, which will be turned
brown, showing thatthe vapor is alkaline; this is owing
to the presence of ammonia (NHj), whicli is almost in-
vai'iably produced when an organic compound contain-
ing nitrogen is decomposed by heat. The odor of the
fumes should also be noticed, and contrasted with those
formed in the last experiment.
105, Heat a little gypsum or sulphate of lime (CaO,
SOg+SAq) in a tube, and note whether it undergoes
any change. It parts with the two equivalents of
' In this and most of the following experiments, espeoially mhen the
substance opernted on is of a deleterious or poisonous nature, the
quantity used should not exceed a pin's head in aize.
' When o tube is at all soiled in an experiment, it is unfit for fiirlber
siGooi^le
THE MOUTH BLOWPIPE. 59
water of ciystjilHzation, whicli contleiise in the upper
part of the tube.
106. Treat a crystal of sulphate of iron (PeO,S03+
7Aq) in a similar manner, observing the successive
changes whieli are produced, and examine the liquid
which condenses in the upper part of the tube, with
litmus-paper.
"When fii-st heated, six equivalents of water are ex-
pelled, leaving a whitish powder, wbieh consists of the
sulphate with one equivalent of water (FeOjSO^iIIO).
On continuing the heat, the sulphunc acid is volatilized,
a portion of it being decomposed by the protoxide of
iron, which is converted into peroxide by the oxygen
derived from the acid.
2CFe0,S0,)=S0j+SOi+Fe,0s.
107. Repeat the experiment, using sulphate of potash
(KOjSOg) instead of sulphate of iron ; the decrepitation
is owing to the escape of a little water, which is me-
chanically lodged between the plates of the crystals.
The salt undergoes no further change.
108. Sublime a little calomel (I^Cl), and corrosive
sublimate (HgClj) in two separate tubes, and note the
different appearances which are presented in both cases.
109. Heat a little red oxide of mercury (HgOa) in a
tube ; observe the rapid change which itundergoes, and
themiuutcglobulesof metallic mercuiy which condense
in the upper part of the tube. If a glowing match be
introduced while the decomposition is going on, it will
indicate, by its vivid combustion, the presence of free
oxygen, especially if the open end of the tube be loosely
closed with the finger, to retard the escape of the dis-
engaged oxygen,
Hg0.=fli7+2O.
110. Repeat the experiment with some red oxide of
lead (PbgOj), and observe in what respects the results
differ from the last. The yellowish residue which is
left is protoxide of lead or litharge (PbO), one-fourth
of the oxygen being expelled.
PbaO.=3PbO-HO.
in. Heat a little arsenious acid (AsOj) in a tube, and
=vGoo(^lc
tiO THE M OUT n BLOWPIPE.
observe closely the cliauiicters of the crystalline subli-
mate (302).
112. Mix together equal portions of nitre (KOjNOs)
and bisulphate of potash (KO,IIO,2S03), and heat the
mixture in a tube ; test the nitrous vapor which is given
off, with litmus-paper, and endeavor to account for its
formation.
113. Heat a mixture of pounded fluorspar (CaF)aud
bisulphate of potash {K:0,H0,2S0,) in a glass tube.
The corrosive action on the glass is owing to the for-
mation of hydrofluoric acid (^F).
KO,HO, 2S0s+ CaF=KF+ CaO,SOs+K0,S0a.
114. Mix a little iodide of lead (Pbl) with bisulphate
of potash, and heat the mixture in a tube : the beautiful
violet-colored vapor which rises and condenses in the
upper part of the tube is iodine.
PbI+K0,H0,2S0,=Pb0,S0s-|-K0,S0s+H+L
115. Puse a little phosphate of lead (3PbO,PO,) on
charcoal, and observe the semi-transparent crystalline
appearance of the bead on cooling (412).'
116. Heat a little oxide of zinc (ZnO)
Big- 49. on charcoal ; observe that it assumes a
f yellow color when heated, but becomes
white ao;ain on cooling.
117. BTotice the change of color that
ensues when ehromate of lead (PbO,Cr05}
is gently heated, and observe whether the
yeflow color returns on cooling.
118. Repeat the experiment with red
oxide of mercury (HgO^), takingearethat
chareoai-LoidBr. the heat is not raised so high as to cause
decomposition (109).
119. Mix together a little chalk (CaO,COj) and char-
coal, and ignite the mixture in a tube ; eai'bonie oxide
' When charcoal ia used aa a support in blowpipe experiments, it
should be cut into slices about the third of
a small cavity scooped out with the point of a knife, in which to lodge
the substance to be heated. The charcoal niaj be conveniently held
during the experiment in a loop of tin plate, in the manner shown in
Fig. 49.
=vGoo(^lc
THE MOUTH BLOWPIPE. bi
gas is given oftj whicli, if formed in sufficient quantity,
will burn with a blue flame.
CaO,CO«+C=CaO+200,
120. Heat a email crystal of carbonate or any other
salt of soda on platinum wire (which should be fased
into a glass handle, and bent at the end, as shown in
Fig. 48), and observe the intense yellow color it com-
municates fo the blowpipe flame. Then wash the wire,
and compare its action on the flame with that caused
by the soda.
121. Repeat the experiment, using nitrate of atrontia
(SrOjNO^) instead of the soda : the color of the flame
will become ci'imBOii.
122. Heat a httle chalk or marble (CaO,C02) on char-
coal, and note the dazzling white light which is pro-
duced, showing that the illuminating power of flame is
not dependent only on the degree of heat, but on the
presence of some solid matter in the flame ;' since the
blowpipe flame, which heats it, and whicli is of course
at least as hot as the lime, emits scarcely any percepti-
ble light.
During the ignition, the carbonate of lime is decom-
posed, and caustic lime (CaO) is left, the alkaline nature
of which may be shown by placing a fragment of it,
after ignition, on moistened turmeric paper, which will
become brown at the point of contact.
123. A piece of alumina {Al^) oi' alum _(AljOs,3S03
-|-KO,S05-|-24Aq) ignited in the flame, radiates a faint
bluish light.
124. Dip a glass rod in a solution of nitrate of cobalt
{CoO,NO^, and moisten a small ciystal of alum with it;
then ignite it on charcoal for a few minutes, and ob-
serve the beautiful blue color which it assumes. This
is a highly characteristic test for alumina.
125. Repeat the experiment, with sulphate of magne-
' See Daniell's Chemical Philosophy, p. 361 .
=vGoo(^lc
62 THE MOUTl! BLOWPIPE.
Bia (MgO,SOa+7Aq), which, when ignited with nitrate
of cobalt, gradually assumes a pale rose color.
126. A salt of zinc, as the sulphate (ZnOjSO^+TAq),
when similarly treated, becomes gi'een.
It ia easy therefore to distinguish between alumina,
magnesia, and zinc, in this simple manner.
127. Heat a fragment of tin in the deoxidizing flame
until it fuses into a bright metallic globule ; when white
hot, throw it on the table, when it will divide into
numerous email globules, which run rapidly about,
burning with a white light, and leaving behind them
white trains of oxide (SnO^).
128. Heat another fragment of tin, and keep it fused
and bright in the deoxidizing flame for two or three
minutes; then oxidize it in the outer flame, and again
reduce it to the metallic state.
129. Heat a little acetate of lead {PbO,C,Hp3+3A<i)
on charcoal ; observe first the liberation of acetic acid
(HOiOjHjOt) and the deposition of a portion of the car-
bon ; and on a further apphcation of heat, the oxide of
lead firet deposited ia reduced to the metallic state, es-
pecially when it is kept, in the deoxidizing flame. The
yellow ring which surrounds tire metallic bead is pro-
toxide of lead (PbO).
130. Reduce oxide of bismuth (EigOg) in the same
way : compare the beads of the difierent metals thus
obtained, as to outward appearance, crystalline struc-
ture, malleability, &c.
181. Heat a small distal of sulphate of copper (CuO,
SOj+SAq) in the reducing flame on charcoal, and ob-
serve the successive changes which it undergoes; first
into black oxide (CuO), and ultimately into a bead of
metallic copper. Hammer out the globule, so as to
render visible its peculiar color.
132. Mis together a little sulphate of baryta (BaO,
SO3) and charcoal in a mortar, and fold a small quantity
of the mixture under one comer of a slip of platinum
foil (Fig. 50). Heat it strongly in the blowpipe flame,
and when the ignited mixture is cool again, put it into
a small tube, and treat it with a drop or two of dilute
hydrochloric acid (HC'l). Observe the efl'ervesceiice
=vGoo(^lc
3 dccom-
eaused by the escape of hydro-sulphuric acid gaa (hs),
which may be recognized by its peculiar odor, and by
a piece of paper moistened with a
solution of acetate of lead, which is ^'^" ^'''
instantly blackened by it (438). In
this experiment the sulphate of
baryta is deoxidized by the charcoal,
becoming sulphide of barium (EaS),
which, when acted on by hyelroehloric acid,
posed, and hydrosulpbunc acid liberated.
Decomposition during ignition.
BaO,SOs+20=BoS+2CO,.
Decomposition caused hy the hydroiJiioric tickl.
Ba,B-\-IICl^Ba CS+HS.
133. Sublime a little sulphur in a small tube open at
both' ends; while in the state of vapor in contact with
the atmospheric oxygen, it becomes converted into sul-
phurous acid (sOj), the presence of which may be shown
by its property of reddening htmue paper when mois-
tened, and bleaching it when dry: its smell also is well
known and chai-acteristic.
134. Heat a small quantity of sulphide of antimony
(SbS^) in an open tube (T'ig-
51) ; observe the formation of
oxide of antimonj' (SbO,)
which appears as white fumes,
and test for the presence of
sulphurous acid (soj as in the
last experiment. Here the
oxygen of the air has oxidized
both the sulphur and the me-
tal.
135. Scoop out a cavity in
a piece of charcoal a (Fig. 52),
and nearly fill it with a paste made of phosphate of lime
{8CaO,3P05) and water, b ; dry it on
the sandbath, and when quite dry, '''^-^^^
place a fragment of lead upon it. Ex-
pose it to the oxidizing flame, and ob-
serve that the oxide of lead (PbO) as
it is formed, is absorbed by the porous
=vGoo(^lc
04 THE MOUTH ELO IV I'IPK.
phosphate of lime, while any silver which may be pre-
aent, ie left unoxidized, aa a small metallic bead. This
process is called eupellation.
136. Fuse a little carbonate of aoda (NaOjCO^) ou
charcoal, and observe that it is absorbed, owing to the
capillary attraction of the porous charcoal.
137. Make a bead of glass, by fusing a mixture of
carbonate of soda and siUca (SiOg) (427).
138. Add a little sulphate of limeto the bead formed
in the last experiment : heat it strongly in the deoxidiz-
ing flame, and remark the yellow color which it as-
sumes, owing to the formation of sulphide of sodium
(Na8).
NaO,SiO3-J-CaO,S0,=CaO,SiOs-|-4O+NaS.
139. Mix a little black oxide of manganese (MnO^) with
_, „ carbonate of soda (NaO,COj), and fuse it on
platinum wire: remark the characteristic
green color which is produced (267).
140. Mix together a little arsenious acid
(AsOg) (a quantity not greater in bulk than
a small pin's head) {801) and black flux
(which is a mixture of carbonate of potash
and finely divided charcoal (751) ) ; ignite
the mixture in a tube closed at one end,
and observe the enist of metallic arsenic
which is deposited in the upper part of the
tube (Fig. 53) (303).
141. Eomove with a file the closed end of the tube
used in the last experiment, and holding it diagonally,
direct the flame of the blowpipe on the arsenic^ cruet;
notice the white crystalline deposit of arsenious acid
(AsOj) which condenses in the cool part of the tube, and
examine with a lens the beautiful octohedral crystals of
which it is composed (Fig. 54).
142. Place a little calomel fflgCi) or corrosive sub-
limate (HgCl^) at the bottom of a tube, and cover it for
about half an inch with dry carbonate of soda (NaO,
COj) ; and make the upper portion of the salt quite
hot, and cariying the heat doivnwards sublime the
calomel througli it. Metallic mercury is deposited in
=vGoo(^lc
SPECIFIC GRAVITY. 65
the form of minute globules in ^'s-^
the upper part of the tube ^ <I
HgCl+NaO,CO,=NaCl+a3+0+GO,. S ^,^"5^
143. Fuse a little borax (Ea. ® ^V '9l^
O,2BO3+10Aq) on a platinum aTJ^ HTW
wire, and observe the color ^^ ^^ '^^t
given to the bead by salt, iron, -|, ^ -^^ ^^
cobalt, copper, lead, manganese, "^ v?^ r> ^
&c., both in the oxidizing and |^ ^ ^
reducing flame. irsomoua Acid.
144. Repeat the same series
of experiments, using carbonate of soda (NaOiCOj),
and afterwards microcosmie salt (N'aOjNH^OjHOjPO^-f-
8Aq), instead of borax, and observe in wbat respects
the results differ from each other.
CHAPTEK VI.
SPECIEIC GRAVITY.
By specific gravity is meant the comparative weights
of equal bulks of various kinds of matter. It hasbeen
found convenient to compare the specific gravities of
all solids and liquids with that of water, which is
reckoned as l-OOO or 1000. The specific gravity of sub-
stances heavier tban water is consequently represented
by a bigber number, and tbose which are lighter by a
lower number, than 1-000 ; that of lead, for instance,
whicb is more than eleven times heavier than water, is
represented by the number 11-35 ; while that of ether,
whicb is considerably lighter than water, is represented
by the number 0.724.^
SECTION I.
Spacific gravity of solids heavier than water.
145. Wben the substance is solid and insoluble in
water, its specific gravity may be ascertained in the
following manner. Weigb it first in air, taking care
' See Fownes'a Manual of Cliemistry, p. 3.
siGooi^le
to remove any duet or loosely-adheriDg
particles. Then suspend it by means
of a horsefiair, from a hook attached to
the scale-pan, making a small loop at
one end of the hair, passing the other
end throug'h it, and inclosing the sub-
stance in the noose. Thus suspended, it
is immersed in water (Fig. 55), and care
should be taken that it is covered on all
sides by at least half an inch of water.
Small bubbles of air frequently adhere to
the surface, and these must be brushed
off with a feather or camel-hair pencil, as
they would tend to buoy it up, and
cause the specific gravity to appear too
low.
The results may be noted down as follow :
Weiglit of tte substance in air . . . ^
" " in water . . =
which number represents the weight of an equal bulk
of water. Then by dividing the weight in air by the
loss, or the weight of an equal bulk of water, the speci-
fic gravity is ascertained.
Weight in air
= specific gravity.
In this way determine the specific gravity of some of
the following substances : — marble, amber,
iron-pyrites, sulphate of baryta, jet, lead,
zinc, glass, and agatc.^
SECTION II.
Specific gravity of solids lighter than water.
146. If the solid be lighter than water,
as cork, a slight modification of the above
Weigh the substance first in air; then
' The following are the specific gravities of these Hnhstances, some of
■which, however, vary considerably. Marble 2" 70 ; amber 1'08; iron-
pjritea 4-90 ; sulphate of barj-ta 4-47 ; jet 1-30 ; lead 11-35 ; zinc 7-00 ;
flint glasa 3-30; and agate 2'60.
=vGoo(^lc
SPECIFIC Gil A VI'IY. G7
select a piece of lead of sufficient size to sink the light
body in water when attached to it, and weigh it (the
lead) in water, suspending it by means of a hair loop,
as before. If now the light substance be inclosed in
the same loop with the lead (Fig. 56), and imniei'sed in
water, it will he found that they will together weigh
less than the lead did alone, owing to the buoyancy of
the lighter body ; and this difterence, when added to
the weight of the body in air, is equal to tlie weiglit of
a corresponding bulk of water.
The results may be thus recorded :
Weight of body in air =
Weight of lead alone in water =
Weight of lead with body attached, in water =
Difference =
Add weight of body in air = ^___
Weight of an equal bulk of water . . . . ^
Having thus obtained the weight of the body in air,
and the weight of an equal bulk of water, the specific
gi-avity is calculated as before.
Weight In air
— ' = Specific gi'avity.
Weight of eqiial hulk of water
In this way ascertain the specific gravity of wood,
cork, and ebarcoal.''
SECTION III
Specific t/ravit^ of insoluble pomdersi
147. "Wlien the substance, whose specific gravity we
wish to determine, is in the form ot powder or even
small lumps, it is clear that some other method must
be adopted than those just described. The following is
the most simple, and for common purposes, sufficiently
accurate. Counterpoise* a small bottle furnished with
' The Bpecifle gravity of these snbstancea varies considerably, ac-
cording to the degree of porosity ; the following may be considered as
the nsual average : wood (beech) 0-85 ; cork 0'34 ; and charcoal 0'2
to 0-5.
^ This is done by putting shot or strips of lead in a pill-box, which,
when placed in the opposite scale, are adjusted until their weight is
equal io that of the bottle.
siGooi^le
68 SPECIFIC GRAVITY.
a stopper ; then fill it completely with distilled water,
close it with the stopper, taking care that no buhbles
of air are left in, and weigh to determine the quantity
of water it contains.'' Having done this, empty the
bottle, and dry the inside either with a cloth, or with
fragments of filtering paper.
It mnat now he filled about two-thirds full of the
powder to be examined, again weighed, and the bottle
then filled cautiously with water, care being taken that
all air-bubbles are expelled, and that none of the powder
is washed out. Again weigh.
Prom the data thus obtained, tlie specific gravity may
he calculated as follows :
Weight of the powder and water . . , ^
Weight of the powder alone = _____^
Difference ^^ weight of water left in the bottle
Weight of bottle full of water . . . . =
Water left in tlie bottle after the powder ) _
■was added i "
Weight of water displaced bj, and equal 1 _
in bnlk to, the powder .... j ~
Then as hefiire :
Weigbt of the powder
cific gravity.
Weight of water displaced
In this Wily ascertain the specific gravity of sand,
pounded glass, and sliot.^
SECTION IV.
Specific gravity of liquids.
148, With a bottle similar to that used in the last
experiment, the specific gravity of liquids may be
readily determined. As the space occupied by a given
weight of liquid varies with the temperature, or, in
other words, as the weight of a given volume of any
liquid is greater or less aa the temperature is lower or
' Bottlee may be purchased which are made to contain exactly 1000
grains of distilled water.
^ The specific gravity of aand ia about 2'GO ; flint glass 3'30 ; and
shot n-35.
=vGoo(^lc
SPECIFIC GRAVITY OF LIQUIDS. 69
higher, it is necessai-y to observe that the tempera-
ture of the lictuid during the experiment does not
vary much from 62°, which is usually taken aa the
standard. I'or the same reason the bottle should not
be touched by the warm hand during the experiment,
as otherwise the heat would cause the liquid to
expand, and become specifically lighter; this may
be avoided by interposing a linen cloth between
the hand and the glass.
Counterpoise the bottle, and weigh it full of
distilled water ; then, bj^ filling it successively
with other liquids, weighing, and comparing the
different weights with that of water, the volume
of liquid being always the same, the specific
gravity is obtained by proportion, thus :
Weighlofbolllefnllorwaler ; I'MO : : WeiBhl of Hguid ; Specifie gruvili'.
Care must be taken to clean the bottle tho-
^^_^ roughly after each experiment, by washing it
specrfio- fi^* With distilled water, and then with a little
graTity (jf the liquid whose density is to be ascer-
tained.
Some of the following may be taken for practice : —
Alcohol, solutions of chloride of sodium, sulphate
of magnesia, alum, carbonate of soda, sulphate of
lime, sulphate of soda, bicarbonate of soda,
sulphate of copper, nitrate of potash, sulphate
of zinc, and cream of tartar.
149. The specific gravity of liquids may also
be determined by another process, which,
though not capable of so much accuracy as the
last, is frequently useful when the specific
gravity bottle is not at hand.
Take a piece of solid glass rod, about the
size of the figure (Fig. 57), with one end drawn
out and turned in the blowpipe flame. "Weigh
it first in air and then in water, suspending it
with a hair-loop (Fig. 58). Then, having wiped
it dry between each experiment, weigh it successively
in the liquids, the specific gravities of which are to be
determined. The difference between the weight of the
glass in air and in the liquid, representing in each case
=vGoo(^lc
70 HEATING SGESTAKCES IN GASES.
the weight of a volume of the liquid equal to that of
the glass, and knowing the weight of a similar volume
of water, the specific gravity may be known by simple
calculation.
Thus :
Weight of glass in uir
Weight of glass in liquid
which is the weight of an equal volume of the liqnid,
Then by proportion, —
Weightof equal I , ^-f, t Weight of equal ( ( Specific gravity (
volume of water.} = ^""" = = jvolumeof liquid) '■ ( of tlie liquid. (
Determine in this way the specific gi'avitiee of some
of the solutions already mentioned, and compare the
results with those obtained with the specific gravity
bottle.
CHAPTER YII.
HEATING SUBSTANCES IN GASES.
SECTION I.
Seduction of metallic oxides by hydrogen.
150. A LARGE number of the metallic oxides are de-
composed and reduced to the metallic state when heated
in an atmosphere of dry hydrogen gas ; and from the
facility with which the operation may be performed,
and the accurate results it gives when carefully con-
ducted, it is frequently employed in estimating the
quantity of oxygen present in oxidized compounds,
151. The apparatus which is required for the pur-
pose is shown in the figure. (B'ig. 59.) The bottle
a is charged with zinc and dilute sulphuric acid to
generate the hydrogen, which is dried whiie passing
over fragments of chloride of calcium in the tube e ; the
gas then pseses into the bulb-tube h, which contains
the oxide to be reduced, the bulb being heated by the
lamp placed beneath.
=vGoo(^lc
METALLIC OXIDE
152. Take a piece of tubing e, about twelve or fifteen
inches long, and half an inch internal diameter, and
having slightly fused the cat edges in the bloivpipe
flame (^^5), iilij" t a eoik to eich end then, ^ ith i coik-
borei oi loundtleperfoiite the corks boi'^ to recent the
small tubes d and m. When the tube is of such a dia-
meter Eia cannot be exactly matched by any of the cork-
borers in the set, the hole should be bored by a smaller
one and afterwards enlarged by means of a round file,
until it JB of sufficient calibre to admit the tube, which
must always fit perfectly tight. E«move one of the
corks from the large tube, and push down to the other
end a small loose bit of tow or cotton wool, and neai'ly
fill it with fragments of chloride of calcium (734) ; put
in another bit of tow (the use of which is to prevent
any of the smaller fragments tailing out), and again fix
the cork and small tube.
IText adapt a cork to the bottle, which should have a
tolerably wide neck, and bore in it two holes to fit tho
tubes 6 and o, which pass through it, the former reach-
ing nearly to the bottom of the bottle, the latter passing
only just through the cork. Put 800 grains of granu-
lated zinc into the bottle, and fix the cork containing the
tubes 8 and c.
153, In order to connect the difierent parts oftheap-
pai'atus together, make two caoutchouc connectors/ and
g. This IS done by loosely folding a piece of sheet
caoutchouc about an inch and a half square, round a
piece of rod or tubing of the same diameter as the tubes
=vGoo(^lc
72 HBATINa SUBSTANCES IN GASES,
which it is intended to joiu together, and cutting off
with one stroke of a pair of sharp seissore the eiiper-
fluous enda (Fig. 60) ; when this is properly done, the cut
edges cohere, and when slightly pressed together bythe
thumb-nails, the junction becomes almost as strong as
any other part of the tube. Care must be taken to
avoid touching the newly-cut edges, as the least dirt or
moisture upon them would prevent them cohering
properly together. It is then carefully removed from
the rod, and ia ready for use.
154. Having made two of these conneetorB, weigli the
bulb-tube accurately, and place in the bulb 20 or 30
grains of oxide of copper (OuO) : again weigh, to as-
certain the weight of oxide operated on, and connect
the apparatus as shown in the figure. The caoutchouc
tubes should be firmly tied round with strong twine or
sillr, which should be passed under and over, and tied
at each half revolution tj insure perfect tightness of the
joint. The apparatus being thus arranged, fill the bot-
tle a about one-third full of dilute sulphuric acid {con-
sisting of one part by measure of the strong acid and
eight parts of water), pouring it down the funnel-tube
b (12) ; and when the gas has been coming over about
five minutes, apply a gentle heat to the bulb, and gra-
dually increase it as long as any water is formed.
CuO+H=Cu^-HO.
It is necessary to observe the precaution of not ap-
plying the heat immediately, since the apparatus at first
contains an explosive mixture of hydrogen and common
air, which would, if heat were applied, be in gi-eat
=vGoo(^lc
danger of exploding (17) and seriously injuring the
opei-ator ; by allowing five minutes to elapse, however,
the whole of the common air is expelled, and tliG bulb
may be heated without danger.
155. "When the decomposition appears to be com-
plete, no fresh water being produced,' expel by heat any
moisture that may have condensed in the cool end of
the tube, remove the lamp, and allow the bulb-tube to
cool; then disconnect the apparatus, and weigh the
bulb containing the reduced metallic copper, the loss
of weight indicating the quantity of oxygen that has
been removed. Ascertain by calculation the percentage
of oxygen in 100 parts of the oxide, and compare the
experimental result with what is theoretically correct,
the atomic weight of copper being thirty-two, that of
oxygen eight, and that of the oxide forty.
Heating suhstances in an, atmosphere of carbonic acid.
156. It is sometimes required in analysis to separate
two substances, one of which is volatile at a high tem-
perature, and the other fixed, so that by merely heating
the mixture, and weighing before and aftei'wards, the
weight of each ingredient is determined. In some
cases, however, it happens that the non-volatile body
when heated in atmospheric air, combines with oxygen,
forming a volatile compound ; so that here it is neces-
saiy to conduct the operation in an atmosphere of some
gas incapable of combining with it, as hydrogen or
carbonic acid. For instance, in the analysis of gun-
powder, which consists of a mixture of nitrate of potash
(KOjKOj), sulphur, and charcoal, the nitrate of potash
is first dissolved out with water, and the insoluble
residue, consisting of sulphur aud charcoal, is heated in
a current of hydrogen or carbonic acid, when the sul-
phur, being volatile, is expelled ; whereas, if the mix-
' This ia known bj holding a piece of cold glass close to the opening
at the end of the tube, and observing whether any moisture is condensed
upon its surface ; if not, it may be inferred that no water ia coming
=vGoo(^lc
74 HEATING SUBSTANCES IN GASES.
ture were to be heated in common atmospheric air, the
carbon as well as tlie sulphur would disappear, since it
would combine with oxygen, and become converted into
carbonic acid (co^) which is a gas.
157, The apparatus required for this pm-pose is tlie
same &s that used for the reduction of metallic oxides
by hydrogen (151). Fill the generating bottle a about
one-third full of water, and put in some fragments of
marble (CaO,COj) ; when the apparatus is aiTanged,
pour in fi-om time to time a little hydrochloric acid
through the tube 5, so as to maintain a moderate efier-
vescence (19). Weigh the bulb-tube, and put into it
about 10 grains of the mixture of sulphur and charcoal ;
weigh a second time, to ascertain how much is need in
the experiment, and connect the apparatus togetlier.
Allow the gas to come over for about five minutes,
in order to displace the common air (which might
otherwise cause the volatilization of some of the char-
coal, by conversion into carbonic acid), and then heat
the mixture as long as any sulphur is volatilized. As
soon as the apparatus is cold, weigli the bnlb-tube again,
when the loss of weight will represent the quantity of
sulphur contained in the mixture. The percentage of
sulphur is then ascertained by calculatiou.
Weight of mixture : loss of weight : ; 100 ; percentage of sulphur.
SECTION III.
Preparation of purchloride of iron (FejClj).
158. "When metallic iron is heated in a current of
chlorine gas, the two substances combine, forming per-
ehloride of non. The chlorine is generated in a retort
a (Fig. 61), to the beak of which a tube, bent at right
angles 5, should be adapted by means of a perforated
cone. The retort is then charged with 700 grains of a
mixture of black oxide of manganese (MnOj and com-
mon salt (NaCI), (in the proportion of three parts of the
former to foiir of the latter), on which should be poured
two ounces of water. Bemove tlie tube-funnel b from
the bottle used in the two last experiments (151), and
snbstitute a piece of tubing e, sufficiently wide to admit
=vGoo(^lc
PEEPAKATIOK OF PEECIILOEIDE OF IRON. 75
the bent tube 6, and reaching nearly to the bottom of
the bottle, which should be filled about a fourth part
fall of water. The rest of the apparatus ia the same as
that used in the reduction by hydrogen (151), only sub-
stituting the straight tube d, which may be six or eight
inches long, for the bulb-tube before employed ; and
put into it thirty grains of clean iron wire.
159. When the apparatus is connected together,
slowly pour into the retort through a funnel one ounce
of strong sulphuric acid {HO,SO^, to disengage the
chlorine from the mixture of manganese and salt ; and
if the gas does not come over properly, apply a very
gentle heat.
Mii05+NaCl4-2 {RO,SO,)=MnO,SO.t-\-NaO,80^-^2HO->rC\.
The gas, when generated, passes through the water
in the bottle/, which retains any hydrochloric acid with
which it may be impregnated ; and having passed over
chloride of calcium in the tube c, arrives in the tube
containing the iron, in a pure and dry state.
When the apparatus ia filled vrith the chlorine, appljy
a gentle heat to the iron wire, and observe the beauti-
ful scaly crystals of sesquichloride of iron (F&Jd\^,
which sublime and condense in the cool end of the
tube. Remove a few of the crystals from the tube, and
remark with what avidity they absorb moisture from
the air when exposed to it for a few minutes.
Dissolve a little of the chloride in distilled water, and
add ammonia {NE^ in slight excess : the brown preci-
pitate which is produced, is hydrated peroxide of iron
(280).
=vGoo(^lc
ALKALIMETRY.
CHAPTER VIII.
ALKALIMETRY AND ACIDIMEXRT.
SECTION I.
AlkaHmetri/.
160. The process of alkalimetry has for ita object the
determination of the quantity of real alkali or alkaline
carbonate in any given sample, and is founded on the
principle that the quantity of alkali which is neuti-a-
lized by a known quantity of acid, ia always
constant and uniform, in obedierice to the well-
known laws of combination in definite pro-
poi-tiona.
For example, forty-nine parts, by weight, of
oil of vitriol {HO,SO^ combine with thirty-two
pai'ts of soda (NaO), and when the two sub-
stances are brought together in these propor-
tions, the resulting compound (sulphate of soda
!NaO,SOg) is a perfectly neutral salt : but if the
relative quantity of acid or alkali be greater or
less than those specified, then there will be an
excels of one of them present, and the solution
containing them will be no longer neutral to
teat paper. Hence it appears that if we have an
unloiown quantity of pure alkali in a solution,
we can, by treating it with an acid of Icnown
strength, and observing how much of the acid
is required to neutralize it, readily determine
mi^tpc the percentage of potash or of soda in any
'^*'*- specimen.
161. The apparatus employed for this purpose is a
tube, capable of holding 1000 ^ains of distilled water,
graduated into 100 parts, the divisions being numbered
from the open end downwards, as in the figure (Fig. 62).
At65degl'eesthereie aline scratched, marked earbonate
of potash ; at 54-6, another line, marked carbonate of soda ;
at 49, ■potash ; and at 23-5, soda ; numbers, it will he
observed, which, when deducted from 100, bear similar
relations to eaeli other as the atomic weights of the
=vGoo(^lc
77
compouuda whose names they are associated with.
Now, if sulphm-ic acid of the specific gravity, 1-1268, be
poured into the tuhe up to the point marked by either
of these names, the quantity of acid thus measured oft
will be exactly sufficient to neutralize 100 grains of the
alkali specified ; and when the tube is filled up to zero
with water, it is evident that each division of the tube
contains the quantity of acid requisite to neutralize one
grain of alkali, being rh^ P^rt of the whole. By as-
certaining experimentally therefore how many of the
divisions full are required to neutralize the alkali pre-
ilOO
gra.
peclmen, that number
will represent the percentage of real alkali which it
contains.
162. Ascertain the quantity of dry carbonate of soda
(NaO,CO,) in a eampie of the crystallized salt {NaO,
COj+lOAq). For this purpose weigh out 100 gi'ains of
the salt, and dissolve it with
the aid of a gentle heat, in
about four ounces of water in
an evaporating basin. Pour
a little of the standard sul-
phuric acid (specific gravity
1-1268) (which should have
been previously prepai-edand
allowed to cool,)' into a lip-
ped glass, and thence into the
albahmeter tube, until it
reaches the line marked car-
bonate of soda, and fill it with
distilled water up to zero.
I'ut two or three small pieces
of litmus and turmeric paper
into the alkaline solution,
which should be kept gently
heated over a lamp, and have
' Salphnrie acid of the specific gravity 1'12G8, may be prepared hj
mixing together one part by meaeure of strong oil of vitriol (HO,SOs)
specific gravity 1-84, and eight parts of diatilled water. Before taking
it into uae, it must be tested both sa to its epeciflc gravity, and also aa
to its neutraliaiog power, which must be ascertained by experiment wit
a pure specimen of alkali.
=vGoo(^lc
78 ALKALIMETRY.
at hand a glass rod to stir it with during the process
of neutralization.
163. Having made these preparations, take the tube
in the left hand, close the opening tightly with the
thumb, and invert the instrument five or six times suc-
cessively, in order to mix the acid and water thoroughly
and uniformly together: then by cautiously relaxing
the thumb, allow tlie acid to Ml drop by drop into the
alkaline solution, stirring the latter constantly with the
glass rod until the litmus begins to turn feebly red.
(Fig. 63.) "When the change of color begins to appear,
v/am the sides of the basin, by gently agitating the
liquid in it, in order to dissolve any of the splashings
that may have dried during the process, and escaped the
action of the acid. "When the point of neutralization
is nearly attained, bring one of the pieces of litmus-
paper from time to time out of the solution against the
heated side of the basin ; if the redness disappears,
more acid must be added, the reddening being tliua
proved to have been caused by the carbonic acid dis-
solved in the water ; and the cautious addition of acid
must be continued until a permanent feeble red color
is obtained.
164. When the neutralization is complete, restore
the tube to its vertical position, and remove the thumb
(which until now should not have been for a moment re-
moved), scraping it gently, so as to separate most of the
adhering acid. Allow the tube to remain upright for a
minute or two, in order that the sides may drain, and
then observe the degree at which the acid stands, that
number representing the percentage of dry carbonate
in the sample.' The decomposition may be thus ex-
N'aO,CO,+EO,S0:=mO,SO^+ 110+00^.
165. Determine the quantity of soda (KaO) in the
same sample. This is done in the way described in the
' The atomic weight of crystalliEed carbonate ofaoda (NaO,COa+30
Aq) being 144; and that of the diy salt (NaO,COs) 54, the percentage
of the latter, supposing the crystallized salt to be pare, may be calcu-
lated aa follows;
144 ; 54 : ; 100 ; x =^ percentage of drj carbonate of soda.
=vGoo(^lc
ACIDIMBTIIY. 79
last experiment, but instead of filling the tube up to
the mark carbonate of soda witb acid, it is filled up to
the mark soda, and then up to zero with water.'
166. Ascertaiu experimentally the percentage of
potash (KO), and of dry carbonate of potash {K0,C02),
m the crystallized carbonate (K0,C0^-j-2Aq).°
Acidimet7'i/.
167. T}ie process of alkalimetry being well under-
stood, that of acidimetry will require but little explana-
tion, as its principle is precisely analogous to thatwhicb
has been described (160). In the former process the
object was to determine the quantity of alkaii by the
quantity of acid which it was capable of neuti'aliaing ;
in aeidimetry, we have to ascertain the amount of real
acid in any solution containing it in an uncombined
form, "WTien the acid under examination forms with
lime, a salt that is soluble in water, its strength may bo
ascertained by determining the quantity of marble or
carbonate (CaO,©©^) which a given
weightofit decomposes and dissolves. ms.si-
This process will serve for nitric, hy-
drochloric, and acetic acids.
168. Determine the percentage of
nitric acid (NO5) in a specimen ot the
liquid acid.
"Weigh out 150 gi'ains of pounded
marble, put it into an evaporating
basin, and cover it with about two
ounces of distilled water. Pour a
little of the acid into a glass, and
thence, by means of a dropping-tube
(99), transfer exactly 100 grains of it
' If tbe crystallized, salt is pure, the percentage of soda may tie cal.
culated ae follows :
Ate. wt-of crystd, carbonaffi ofsoda. Ate. wt. of soda. Per ceiiLof soda-
144 : 33 :: 100 : a;
' The atomic weight of KO is 4S ; that of EO,COj 70 ; and that of
K0,C0a+2Aq 88.
=vGoo(^lc
80 ACIDIMETRT.
into Ji previously counterpoised capsule. Add this in
successive portions to the marble, avoiding too large an
addition at once, lest the effervescence should be so
violent as to cause some of the iiquid to be projected
over the sides of the basin and lost.
When the whole of the acid has been added, wash
out the dish which contained it, two orthree times, with
distilled water, and add the washines to the marble ;
Btu- the mixture repeatedly with a glass rod, and when
the efFerveseence appears to have nearly ceased, heat it
gentiy over a lamp,
CaO,OOj+ -WOs= Ca O.WOs+COj.
169. "While this is going on, fit up a washing bottle
(Fig. 64), the tubes for which have been already pre-
pared (94). Two holes must be bored in the cork to
fit the tubes, which must be fixed in the manner shown
in the figure. Then pre-
pare a filter, according to
the directions already given
(66) ; and having moistened
it with distilled water, sup-
port it over a beaker glass
by means of a retort stand
or perforated block of wood
(Fig. 65). Pour the solution
from the evaporating basin
down a glass rod into the
filter, directing the stream
so that it may Ml upon the
sloping side and not into the
apex, lest its force should in-
jiire orbieak thiouah the paper; wash the last portions
ofmarble out ofthebasinbymeans of the washing bottle,
holding the basin in a nearly vertical position (Fig. 66).
"When the liquid has for the most part passed through the
filter, wash the latter with water from the washing bot-
tle, directing the stream just below the upper edge of
the filter, and continuing to wash until a drop of the
filtered liomidj when evaporated on a strip of glass or
platinum foil, leaves no trace of solid matter. When
this is the case, we may be sure that the whole of the
=vGoo(^lc
A C I D I M E T R Y.
soluble nitrate of limo {OaO,NO^ has been waalied out,
aud that nothing remains but the portion of marble
which was not decomposed. This residue must now
be thoroughly dried, weighed, and its weight deducted
from that of the whole of the marble employed ; the
ditference being of course the weight of that which has
been dissolved by the acid. Now since every equiva-
lent of carbonate of lime which has been dissolved,
indicates the presence of an equivalent of nitric acid,
the quantity of nitiic acid in the 100 grains employed
may be ascertained by the following proportion :
Atomic weight of Atomic weight of
carbonate of lime. nitric acid.
-I, . . . . . ( Quantity of mat- 1 . ,_ ( Percentage
^" ■ ^* ■ ■ ( ble dissolved j ' *^ | of nt. acid.
170. Aseei'taiu the pereentage of hydrochloric acid
(HGi) in a specimen of the liquid acid. Proceed exactly
as in the previous experiment with nitiic acid (168),
only in the calculation substitute the atomic weight of
hydrochloric acid 37, for that of nitric, thus:
50 : 37 :: Qiiiintitj of marble dissolved : x
=vGoo(^lc
82 AOIDIMETRY.
171. In the detei-mination of the strength of acids
which do not foi'ni with lime salts that are soluble in
water, the method just described will not, of eoui'se,
give accurate results ; and the following may be adopted,
which we will consider as used in the case of sulphuric
acid, sulphate of lime being too sparingly soluble to
admit of tliis acid being estimated by the process with
marble.
172. Determine the percentage of sulphuric acid
{}IO,SOi) in a specimen of the dilute acid. Take 100
gi-ains of the acid (weighed in the manner already de-
scribed (168) ) and place it in a tolerably large evaporat-
ing basin ; dilute it with three or four ounces of water,
and wash out with water the dish in which the acid was
weighed, so as to avoid the loss of any of the acid : put
into the dilute acid two or three pieces of litmus-paper,
and heat it gently over a lamp. Dissolve 100 grains of
pure crystallized carbonate of soda (NaOjCO^+lOAq)
in an ounce and a half of water, applying if neeessaiy
a gentle heat, and pour it when coid into the alkah-
meter tube (161), washing with water the dish in which
the solution was made : then fill the tube up to zero
with distilled water. Now take the tube in the left
hand, and having closed it securely with the thumb,
invert it repeatedly, in order to secure the perfect and
uniform mixture of the sahne solution and the water.
"When this has been done, it is evident that each divi-
sion of the alkalimeter tube must contain in solution
one grain of the crystallized carbonate.
The alkaline liquid must now be added gradually to
the dilute acid, -with the same precautions as in the pro-
cess of alkalimetiy (163), until the red color of the
litmus is changed to purpUsh blue ; when this is the
case, remove the thumb, and after allowing the tube to
stand upright for a minute or two, read off the degree
at which the liquid stands ; that number representing
the number of grains of the carbonate which have been
required to neutralize the 100 gi*ains of dilute acid. As
each equivalent of the carbonate which is neutralized
repi'esents an equivalent of the acid, the following cal-
culation will farnish the percentage of the latter :
=vGoo(^lc
ACIDIMETRY.
173. Determine the strength of nitric (NO^) and hy-
drochloric (ffOl) acids by this method, and compare tlie
results with those obtained by the decomposition of
marble (168, 170).
SECTION III.
Estimation of Carbonic Acid in Carlonales.
174. The quantity of carbonic acid (CO,) contained in
any carbonate which is readily decomposable by hydro-
chloric acid, may be determined in
the following manner. Take a piece ^'^* *"'
of tube h (iFig. 67), five or eix inches
long, with one end drawn out so as to
leave only a small opening, and fill it
with fragments of chloride of calcium
(734), putting in a loose plug of tow or
cotton wool at each end, in the manner
already described (152). Bend a piece '^"''""'"^^"J'' ^'^^^
of quill tubing in the form shown at d
(88), and by means of perforated corks, connect the two
tubes with a flat-bottomed flask, capable of holding ten
or twelve ounces of water. Select a tolerably wide
test-tube, of such a size as will stand in the flask in an
inclined position as shown in the figure, and nearly
fill it with strong hydrochloric acid [HGT).
175. Put into the flask twenty grains of mai-ble
(CaO,COj) in small fragments, and poui- upon it about
an ounce of water : then cautiously introduce the tube
e containing the acid, taking care that none of the acid
ia allowed to come in contact with the marble ; connect
the chloride of calcium tube with the flask, and accu-
rately weigh the whole apparatus. Kow gradually in-
cline the flask, so as to allow the acidto flow slowlyupon
the marble : the carbonic acid is disengaged with effer-
vescence ; is deprived, while passing over the chloride
of calcium, of the moisture with which it is impreg-
nated; and passes off'tbi'oughthe small aperture in the
=vGoo(^lc
84 ACIDIMETRY.
tube 5, leaving tlie apparatus of course lighter than
before.
176. When the effervescence has ceased, the flask
should be gently warmed, and wheu cool again, the
cork may be removed, and air di'awii through the flask
by means of a emalj piece of tube, to absti'act the whole
of the carbonic acid with which it ia filled ; and which,
being heavier than common air (22), would add to ita
appai'ent weight. The chloride of calcium tube is then
replaced, and the whole apparatus again weighed ; the
loss of weight being of course that of the carbonic acid
expelled. By multiplying this loss by 5 (20x5=100),
the percentage of carbonic acid in the marble is ob-
tained.
177. Ascertain in the same way the percentage of car-
bonic acidintheearbonat6(NaO,COa+10Aq) and bicar-
bonate of soda (]S'aO,HO,2COjj).
=vGoo(^lc
PART II.
ACTION OF REAGENTS ON BASES AND ACIDS.
Inlroduclori/.
178, Qualitative analysis has for its olajeet the de-
termination of tlie elements of compounds which are
contained in any given eubstanee ; and those elements
and compounds are recognized by certain characteristic
appearancea which they present when exposed to the
action of testa or reagents, or when otherwise ti'eated,
as when submitted to heat, &c.
Before proceeding, therefore, to the more complicated
processes of analysis, it is advisable that the student
should make himself familial' with the action of reagents
on the compounds most commonly met with in such
investigations, in order to enable him properly to in-
terpret the language in which Nature, through his ex-
perimente, replies to his inquiries.
With this purpose in view, he should not merely ap-
ply his teste, and superficially note whether a precipi-
tate is or is not formed, but he should endeavor to im-
press on his recollection the exact appearance which it
presents, both as to color and also as to physical structure ;
whether it is ciystalline, curdy, or gelatinous ; whether
it separates immediately from the solution, or requires
time for its development ; as well as the action of sol-
=vGoo(^lc
80 CLASSIFICATION OF EASES ANTI ACIDS,
vents (as acids and alkalies) upon it. Besides the in-
creased facility which he will thna gain in making snb-
semient experiments, he will beaequiringhabits ot close
ana accurate ohservation, which will be of infinite value
to him, not only in pursuing the study of chemistiyj
but in almost every occupation of life.
SECTION II.
Claisificalion of Sases and Acids.
179. In describing the action of reagents, and the
rudiments of chemical analysis, all the rai'cr bases and
acids will he omitted, as they would only tend to con-
fuse the student.' The following are those which will
be treated of, a8 being most commonly met with iu
analysis. The bases are classified according to their
behavior with hydrosulphurie acid (HS), hydrosulphate of
ammonia iNII^S,HS) and carbonate of soda {J}faO,CO^.
Those in Class IV are precipitated as sulphides from
acidified solutions by hydrosulphurie acid; those in
Class III are not affected by hydrosulphurie acid when
an excess of hydrochloric acid is present, but are thrown
down either as sulpliides or oxides when their neutral
solutions are treated with hydrosulphate of ammonia ;
those in Class 11 are not precipitated by either hydro-
sulphurie acid or hydrosulphate of ammonia, hut are
thrown down as carbonates, by carbonate of ammonia
or of soda : and those in Class I are unaffected by any
of those reagents.
Bases.
Ckm /.
Potash, (KO)
Soda, (NaO)
Ammonia, (NH^)
Class IL
Mngiiesia, . (MgO)
Lime, (CaO)
Baryta, (BaO)
Stroatia, (SrO)
' 111 ilie Appendix will be found a table allowing tlie behavior of
roost of ilie rarai' sulistaiiecs with roagenta.
siGooi^le
CLASSIiriC
BASES AND
ClMS III.
Alumina, . _ (AI.Os)
Oxide of Chromium, . . . . . ( Ci'sOj)
OsideofZiac, (ZiiO)
Protoxide of Maaganes
Protoxide of Iron,
Peroxide of Iron,
Oxide of Nictel,
Oxide of Cobalt,
Oxide of Areeaio (;
Arsenic Acid,
Oxide of Antimony,
Protoxide of Mercury,
Peroxide of Mercury,
Oxide of Lead, .
Oxide of Copper,
Oxide of Silver, .
Protoxide of Tin,
Peroxide of Tin,
Oside of Biamutli,
id),
[Un 0)
(FeO)
(Fe,0,)
(NiO]
(CoO)
(AsOs)
(ASO;)
(SbO,)
(HgO)
(HgO,)
(PbO)
(CO)
(AgO)
(SnO)
(SiiO,)
'0
The acids are divided into two groups, the luorgaoic
and the Orgatiie.
hwrgardc Acicb.
Sulphuric, (SO,)
Pliospboric, . . ... (POj)
Boraeie, . (HO,)
Oarbooic, ('■'•^j
Silicic, (SIC,)
Hydroolilotie, (HCl)
Hydriodic, (HI)
Hydroaulpburic, (US)
Nitiio, [NO^]
Chloric, {OkO)
Organic Acids. .
Oxalic, CHO,G^Oa)
Tartaric, (2 H0,C3H,0,„)
Citric, (3HO,C,5HA,)
Malic, (2 HO.OaHjOs)
Succinic, [HO,C,HA)
Benzoic, (HOjCHHsOg)
Acetic, (HO,C,H,0a)
Formic, {HO,C.Jf„Os)
180. Should the student find that the action of any
test does not agree with that described, it may be owing
=vGoo(^lc
as METALS BELONGING TO CLASS I.
to some impurity contained in the test liquid, in which
case he may examine it in the manner described in the
section on reagents (689).
CHAPTER IL
METALS BELONGING TO CLASS I.
Poiasli, Soda, and Ammonia.
181. TiiE three bases belonging to this class are
chiefly characterized by the solubility in water of most
of their compounds, and the consequent difficulty of ob-
taining them, in an insoluble form, and of separating
them from one another in the shape of precipitates.
They are distinguished from all other bases by produc-
ing no precipitate when tested with either of the three
classifying tests — viz., hydrosulphuric acid, hydrosul-
phate of ammonia, and carbonate of soda, theu- sul-
phides and carbonates being all soluble in water.
Solutions of the uncombmed or carbonated alkalies
are alkaline to test-paper, turning reddenedlitmus blue,
and turmeric brown.
SECTION I.
Potasli (KO).'
A solution of chloride of potassium [KOI) may be used.
182. When a drop of the solution of a potash salt is
evaporated on platinum foil and ignited, it leaves a
fixed residue, in which respect it differs from ammonia
(192).
183. Observe the action of caustic potash, and car-
bonate of potash in solution, on litmus and turmerie
faper.
Test the solution in separate test-tubes with hydrosul-
flmric acid, h^drosulphate of ammonia, and carbonate of
soda. No precipitate is produced in either case.
' Those teats which are most diaiiicteristic are distinguished by (C).
=vGoo(^lc
184. It must be remembered that iu many eases, pre-
cipitates do not separate at once fi-om the solutions, but
require time for their development. This is especially
to be regarded iu the precipitation of those salts which
are to some extent soluble, as the double chloride of
platinum and potassium, hitartrate of potash, ammonio-
phoBphate of magnesia, and many others. In all .such
cases, and whenever there is any doubt as to the appear-
ance of a precipitate, it is better to leave it for a time,
and not to decide that no precipitation will tal^e place
until the mixture has stood twenty-four hours. If, after
that period, no precipitate appears, it may he safely in-
ferred that none will aftei'wards be formed. It is neces-
sary also in these cases, that the solution should be
tolerably concentrated.
185. (0) An alcoholic solution of hichloride of pla-
tinum [PtOQ when added to neuti'al or slightly acid
potash solutions {especially of chloride of potassium),
throws down a fine yellow ciystalline precipitate, con-
sisting of the double chloride of platinum and potassium
(KCljPtClj). The presence of a little free hydrochloric
acid assists the formation of the precipitate, especially
when the potash-salt is any other than the chloride. If
the potash solution is dilute, the precipitate does not
form at once ; so that it is necessary, in employing this
test, when we do not obtain a precipitate immediately,
to allow the mixture to stand some time (184) before
we decide that no potash is present. In such cases, the
best way is to evaporate a mixture of the solution of
chloride of potassium and chloride of platinum nearly
to dryness on a water-batli (645), and treat the residue
with alcohol, which leaves the whole of the double
chloride undissolved.
As ammonia pi-oduces, with chloride of platinum, a
similar precipitate, it is necessary, before deciding that
the indication is due to potaah, to prove the absence of
ammonia (194).
186. (O)Add a solution of tartaric add {'2S0,C,H^
(9,,) in excess to that of thepotash salt, which shouldbe
either neutral or with a slight excess of alkali. A color-
less crystalline precipitate is produced of hitartrate of
=vGoo(^lc
yO METALS BELON&ING TO CLASS I.
potash (KOjHOjCgHPjn). As in the last test, the pre-
cipitate does not appear immediately unless the solution
be concentrated ; so that it must be allowed to stand a
short time before we satisfy oui'selves that no potash is
The separation of the preeipitatej in this and other
similar cases, is much assisted by agitating the mixture
with a glass rod; wherever the rod has rubbed against
the sides of the tube containing it, delicate lines of
microscopic crystals are deposited before any precipi-
tate appears in the body of the liquid.
187. (0) Ignite a small fragment of a salt of potash
on platinum wire in the deoxidizing flame of the blow-
pipe (83), and observe the violet color which it com-
municates to it. A email quantity of the potash (KO)
is here deoxidized, and the volatile potassium (K) thus
formed, is again oxidized while passing through the
outer fiame, which combustion is accompaniocl by the
violet flame.
The same color may be observed in the flame of
alcohol which cont-ains a little potash in solution.
It is to be observed, that in these experiments the
presence of any soda prevents the appearance of the
violet tint, on account of the intense yellow color which
the latter base gives to the flame (190).
SECTION n.
Soda. (NaO).
A solution of sulphate of soda {NaO,SO^-\-~i^ Aq)
may be used.
188. (C) All alcohohc solution of UcMoride of pla-
tinum, (PtOl^) gives no precipitate in solutions of soda
salts, even when they are concentrated. If the mixture,
however, be allowed to evaporate spontaneously, deli-
cate yellow needle-shaped eiystals of the double chloride
of sodium and platinum (NaCljPtCIj) will gradually
form, which are so totally different in appearance from
the coiTcsponding potasli compound (185), besides being
=vGoo(^lc
A M M N I A. 91
readily soluble in water and alcohol, that the two cannot
be mistaken for each other.
189. (C) Antimoniate of potash (KO,SbO^) when added
to soda salts, either neutral or containing a slight excess
of alkali, produces a, white crystalline precipitate of an-
timoniate of Boda (]:iraO,Sb06) (184). If the soda salt
under examination contains an excess of acid, it should
he neutralized with potash before the addition of the
antimoniate, as otherwise a precipitate of antimonic
acid (HOjSbO,) or biantJmoniate of potash (KO,2Sb05)
might be produced, owing to the decomposition of the
antitttoniate by the free acid.
It ia necessary, in employing this test, that both it
and the soda solution should be tolerably concentrated,
as otherwise no precipitate will be produced (184).
190. (C) When a fragment of a salt of soda is heated
before the blowpipe, it communicates an intense yellow
color to the flame ; the same color is produced, also,
when alcohol is mixed with a solution of soda, and
burnt.
191. Keither hydrosulphurie acid, Jiydroaulphate of
ammonia^ nor an alkaline carbonate, produce any preci-
pitate in solutions of soda, neither does tartarie acid
(186).
SECTION in.
Ammonia {NH^ or with one equivalent of vialer, luhicli all ila
sails milh oxygen acids contain (NJI^O).
A solution of muriate of ammonia [NH^Ol] may be used.
192. (0) When heated on platinum foil, the salts of
ammonia ai'c all decomposed ; and (unless the acid, like
the phosphoric or boracic, is fixed at a red heat) vola-
tilize completely, leaving, if pure, no fixed residue.
They may be in this way readily distinguished from the
salts of potash and soda.
193. Like potash and soda, ammonia gives no precipi-
tate with hpdrosulphurie acid, hydroiulpkate of ammonia,
or an alkaline carbonate.
194. (C) Bichloride of platinum (PtOQ throws down
=vGoo(^lc
92
BELONGING
in ammoniaeal solutions, which are not very dilute, a
yellow crystalline precipitate of the double chloride of
platinum and ammonium {WHjCljPtCL;), which is very
similar in appearance to that produced in solutions of
potash (184, 185).
If we are doubtful whether the precipitate obtained
by this test is due exclusively to ammonia, or whether
it contains any potash, the precipitated double chloride
may be ignited, and the residue digested in water ; if
the solution thus obtained give aijy precipitate with
nitrate of silver, potash is present. The reason is this:
the ammoniaeal compound (NH^Gl,PtC]j) leaves, after
ignition, nothing but metalhe platinum; while the
potash compound (XCI,PtCij) leaves a mixture of me-
tallic platinum and chloride of
^'K- ^^- potassium, the latter of which,
when dissolved in water, and
tested with nitrate of silver, gives
a precipitate of chloride of silver
(AgCl) f429).
195. (C) The aalta of ammonia
are all decomposed when gently
heated in a test-tube^ with a Bolur
tion of caustic potash or soda, or
with hydrate of lime {CaO,HO).
The fixed alkali here combines
with tlie acid of the ammoniaeal
salt, on account of its superior
affinity, and seta free the ammonia.
NHiO,S03+J?"0=KO,S03+NH,+ ifO.
The presence of the free ammonia in the upper part
of the tube may be proved,
(a) By its well-known odor ;
(5) By its alkaline reaction on tunnerie and reddened
litmus-paper, which should be previously moistened,
and then held within the tube, care being taken that it
does not touch any part of it; and
(c) By the production of dense white fumes of muriate
of ammonia (HH^Cl), when a rod moistened with dilute
' When a liquid is to be boiled in a test-tnbe, tte latter may bu con-
TOnipiHIy held ill a loop of papei: or cloth, ns shown in Fig. 68.
=vGoo(^lc
MEI'ALS EELONGINO TO CLASS II. 93
hydrochloric acid [HGl) is held near the mouth of the
tube,
196. Tartaric acid (2 RO, OMtO-i^ behaves with ammo-
nia in the same way as with potash, tlu'owing dowu a
colorless crystalline precipitate of bitartrate of am-
monia (NH^OjHOjCgHjOiJ, which is, however, rather
more soluble than the bitartrate of potash (186).
Swrnmary of Class I.
197. From the experiments now described, it appears
that the three alkalies may be distinguished from other
metallic oxides by their producing no precipitate with
either hydrosulphric acid, hydrosulphate of ammonia,
or an alkaline carbonate; one or more of which causes,
as we shall presently see, a precipitate with all other
bases. Hence, if we have a solution which we know
to contain some inorganic saline matter, and we find no
precipitate produced in it on the application of those
tests, we conclude that the base of the salt is either
potash, soda, or ammonia.
For the purpose of distinguishing between the three
alkalies themselves, we may first test for ammonia, by
heating with potash {195J. If this is absent, add to a
tolerably concentrated solution some bichloride of^lfiti-
num or tartaric acid (185, 186), which will enable iis'
to distinguish between potash and soda. If these tests
give no precipitate, It is probable that the base is soda;
which may be confirmed by the behavior of the solution
with antimoniate of potash (189), and by allowing the
mixtur.e with bichloride of platinum to evaporate spon-
taneously, when, if yellow needle-like crystals appear,
the presence of soda may be considered certain (188),
CHAPTEE m.
METALS BELONGINa TO CLASSII.
Magnesia, Lime, Baryta, and Strontia.
198. These bases are distinguished from the alkalies
by the iiisoUibility of many of their salts, especially their
=vGoo(^lc
84 METALS BBLONeiNtl TO CLASS II.
carbonates and phosphates ; so that when treated with
cai'honate or phosphate of soda, they furnish copious
precipitates.
SECTION I.
Magnesia (MgO).
Asohition of the sulphate {MgO,SO^+*t Aq) is the most
convenient for the following experiments.
199. K^either Tiydrosulphuric acid nor hydroBulphate of
ammonia give any precipitate in solutions of magnesia.'
200. {O) Ammonia {NH^ when added to a neutral
eolutipn of magnesia, separates a portion of it in the
foi-m of hydrate (MgO,HO), which appears as a buUiy
white precipitate.
Mfj 0, SOi+NI{,+2HO=UgO,RO+ mf^O,SO.,.
The rest of the magnesia remainsin solution, in com-
bination with the ammonia and acid, forming a soluble
double salt of ammonia andmagnesia(iVS"jO,J^Oj2iS'03).
Most of these double salts of ammonia and magnesia
being soluble in water, andbeing usually formed when
ammoniacal salts are present in excess, the latter have
a strong tendency to interfere with the action of the
reagents, which in the absence of ammonia produce a
precipitate. For example, if the solution of magnesia
be mixed with muriate of ammonia {NHJJl) and then
tested with ammonia as above, no precipitate is pro-
duced.
201. Collect on a filter, and waah with distilled water,
a little of the precipitated magnesia obtained in the last
experiments, and place it while moist on yellow tur-
meric paper ; the magnesia being very slightly soluble
in water, haa an alkaline reaction, and turns it brown.
202. Solution of cauetto potash {KO) precipitates hy-
drate of magnesia {MgO,HO), especially if the mixture
is heated.
. case, the hydroBulpliate coLitaiiis fi-ee
a slight precipitate (2(10).
=vGoo(^lc
MAGNESIA. y&
Aiimioniaeal salts (as muriate of ammonia), if present
ill the solution, prevent tlie formation of this precipitate,
or, if added subsequently, often redissolve it.
203. Qurlonate of potash {KO,GO^ gives a white pre-
cipitate, consisting of basic carbonate of magnesia
(4MgO,30O2+4Aq). A portion of the magnesia re-
mains in solution as bicarbonate, whieb when boiled is
, and the neutral carbonate (MgOjCOj)
J insoluble, is precipitated. Ammoniaeal salts, if
present, prevent the formation of these precipit-ates,
and redissolve tliem if subsequently added.
204. Garhonate of ammonia {^NH^O,WO^ gives no
precipitate unless the solution is boiled, and not even
then unless it be added sparingly.
205. Sulphuric acid {RO,SO^ or sulphate of soda
[J^aOjSO^], produces no precipitate in solutions of
magnesian salts, since the sulphate of magnesia is
soluble ill water.
206. (0) Phosphate of soda {^NaO,SO,P0^) gives a
white precipitate of phosphate of magnesia (2MgO,HO,
POg) provided the solution ia not very dilute, and espe-
cially on boiling.
The addition of ammonia or its carbonate to the mag-
nesian solution, renders the phosphate of soda a far
more delicate test tlian when used alone, because under
those cireumstanees the double phosphate of ammonia
and magnesia (2MgO,NH^O,P05-|-12Aq) is produced,
which is less soluble than the phosphate of magnesia,
and ia consequently thrown down from a more dilute
solution than would furnish a precipitate mth phos-
phate of soda alone. If the solution is vejy dilute, the
precipitate does not appear at once, but if allowed to
standsomelittletime, a crystalline deposit of the double
phosphate gradually separates (184). Agitation of the
liquid with a glass rod hastens the formation of this
precipitate ; and it is remarkable that if the tube be
rubbed at all with the rod during agitation, lines of
minute crystals ai-e there fii-st deposited. The same
phenomenon occurs in the case of the bitartrate of
potash and others, in which tlie precipitate is slowJy
deposited from a dilute solution.
=vGoo(^lc
96 METALS BELONGINS TO CLASS II.
As the double phosphate is readily sohible in an ex-
cess of acid, and slightly so in water, it is necessary
that the solution should be pretty strongly ammonia-
cal. ,
It will be observed that in this test, the effect of am-
moniacai salt-s in the solution is the reverse of that
before described (200), "When mixed with ammoniaeal
salts indeed, magnesia can be precipitated only by a
soluble phosphate.
If the double phosphate be ignited, it is decomposed
into phosphate of magnesia {2MgO,VO^), the ammonia
and water being expelled.
207. Oxalate of ammonia {NH^O,C^O^ gives, in toler-
ably strong solutions, a white precipitate of oxalate of
magnesia (MgOjOjOg), provided no other ammoniacal
salts are present.
208. (C) Baryta water {BaO in water) gradually throws
down a white precipitate of hydrate of magnesia (MgO,
HO) (184). If the sulphate of magnesia be used, the
insoluble sulphate of baryta (BaO,S03) will be thrown
down at the same-time,
MyO,SOi+BaO,HO^'KgO,llO-\-'Ba.Q,'&0^.
209. (C) "When magnesia or one of its salts is mois-
tened with a solution of nitrate of cobalt [CoO,NO^,
and strongly heated before the blowpipe, the mixture
E^enmea a pale flesh or rose color.
SECTION II.
Lime (CaO).
A solution of chloride of calcium {OaQl\ or nitrate of
lime {CaO,NO^-\-'&Aq) maybe used with the liquid
210. Place a small fragment of caustic lime on mois-
tened turmeric paper ; the brown color which is pro-
duced shows the alkaline nature of lime.
211. Sydrosulphurio acid and hydrosulphate of am-
monia give no precipitate in solutions of salts of lime.
212. Ammonia produces no precipitate.
=vGoo(^lc
LIME. 97
213. Potash (JSTO), throws down a wliite precipitate of
hydrate of lime from concentrated eolutions, which re-
dissolves when treated with a large quantity of water,
Ga Gl,-{-K0,R0=Qa.0,110+KaL
If any of the precipitate is insoluble when treated
with water, it is probably owing to the potaali contain-
ing a little carbonate, which would cause the formation
of the insoluble carbonate of iime (214). If the solution
of hydrate of lime be exposed to the air, it gradually
absorbs carbonic acid, and a deposit of carbonate of
lime takes place, which dissolves with effervescence in
dilute hydrochloric acid.
214. (C) Carhonate of potash {KO, 00^) throws down
a copious precipitate of carbonate of lime {CaO,COj),
which is readily soluble with effervescence in dilute hy-
drochloric or nitric acid.
Ca m+KO, CO^^CaO, CO. ,+E:CI.
The quantity of the precipitate increases on boiling
the mixture ; and its formation is unaffected by the pre-
sence of ammoniacal ealta.
215. Sulphuric acid (ROfSO^) or sulphate of soda {Na
0,S0^, when added to concentrated solutions of lime,
give an immediate white precipitate of sulphate of lime
(CaO,803+2Aq).
Ca a-\-Na 0,S05=CaO,S03+if« CI
If the solution is not concentrated, the precipitate
may not appear at once, but will gradually separate in
the form of minute crystals (184); and if the solution is
veiy dilute, no precipitation will take place, because the
sulphate of lime, being soluble in about 500 times its
weight of water, remains dissolved if sufficient water is
present. In solutions of sulphate of lime, of course no
precipitate is produced by either of these reagents.
216. (C) After having thrown down the sulphate of
lime, pour the mixture on a filter, and test the filtered
solution with oxalate of ammonia (218) ; suiScient of
the sulphate will have been rettunedin solution to give
a very perceptible precipitate with the oxalate. For
the success of this experiment, it is neeessaiy that the
=vGoo(^lc
98 METALS BELONQINQ TO CLASS II.
liquid is free from any excess of aeid, since the oxalate
of lime is soluble in moat acid solutions (218).
21T. Phosphate of soda (2iV([O,JT0,PO5) gives, in neu-
tral or alkaline solutions of lime, a white precipitate of
phosphate of lime (80aO,3POj), which is readily soluble
in dilute hydrochloric acid, and reprecipitated from the
aeid solution when neutralized with ammonia." The
presence of ammonia does not, as in the ease of mag-
nesia (206), facilitate the formation of this precipitate.
218. (C) Oxalate of ammonia (NSJ},OJ)s) ia an ex-
tremely delicate test for lime. Wlien added to a solu-
tion containing it even in a highly diluted state, a
copious white precipitate of oxalate of lime (CaOjCjOj
+2Aq) is produced, which is one of the most insoluble
salts with which we are acquainted.
It IB necessary that the solution should contain no
excess of acid, as the oxalate of lime is soluble in aeid
solutions ; acetic and oxalic acids, however, do not dis-
solve it.
219. If alcohol, containing a salt of lime in solution,
is burnt, the flame has a reddish tinge, less crimson,
however, than that caused by strontia under the same
circumsfBnces (236). The salts of lime also communicate
a similar color to the blowpipe flame.
SECTION III.
Bari/ta (BaO).
A solution of chloride of barium {BaC%+2Aq) may be
used with the liquid tests.
220. Hydrosulphuric acid and hydrosulphate of am-
mania produce no precipitate with salts of baryta.
221. Ammonia, when free from carbonate, gives no
precipitate.
222. Potash (KO) in dilute solutions gives no preci-
pitate ; but if the baryta solution be concentrated, it
=vGoo(^lc
tlirowe down a bulky ciystalline precipitate of hydrate
of barj^ {BaO,HO,-|-9Aq), which recliasolvee if water
be added.
223. Carbonate of potash (KO,CO^, and carbonate ot
ammonia (2iV!H40,3C'0j) throw down a white precipitate
of carbonate of baryta (EaOjCOj).
BaCl+KO, GO^^BM,GOt+KCl.
"Wlien seaquiearbonate of ammonia is used, the solu-
tion should bo mixed with a little free ammonia, and
boiled, to decompose any bicarbonate of baryta, which,
if present, would remain dissolved. The precipitated
carbonate is readily soluble with effervescence in dilute
hydrochloric or nitric acid.
224. (0> Sulphuric acid {HO,SO^) and sulphate of soda
{NaOjSOj) produce in solutions of baryta a copious
white precipitate of sulphate of baryta (BaOjSOj) even
in very dilute solutions.
BaCl+NaO,SO^=B&0,BO,+mtCl.
This precipitate is quite insoluble inhydroehloric and
nitric acids, and thus differs fi.'om the carbonate formed
in the last experiment.
225. (0) Solution of sw;^^(rieo/Ime(CaO,^03) throws
down an immediate precipitate of sulphate of baryta
(BaOjSO,). This is the most convenient form of apply-
ing a very dilute solution of a sulphate (sulphate of
lime requiring about 500 times its weight of water to
dissolve it), and serves to distinguish baryta from strontia
(233).
226. Fhosphate of soda {2NaO,EO,PO^ causes a
white precipitate of phosphate of baryta (2BaO,HO,
POc), which is soluble in free acids, but is repreeipitated
when the acid solution is neutralized with ammonia.
2BaCl->r2Na.O,EO,PO^=2'Ba.O;B.O,VOt.-\^2KaCl.
The presence of ammoniacal salts does not affect the
formation of this precipitate.
227. Oxalate of ammonia {NH^OjG^O^ throws down a
white crystalline precipitate of oxalate of baryta (BaO,
CjOg) if the solution is not very dilute (184). It re-
quires a much stronger solution of baryta than of lime
to cause a precipitate with oxalate of ammonia. The
=vGoo(^lc
100 METALS EELOSGIRG TO CLASS IT.
oxalate of baryta, like that of lime, is readily soluble in
free aeida.
228. The flame of alcohol, containing a baryta salt,
has a yellowish color, in which respect it differs from
lime and strontia (219, 236).
SECTION IV.
Sti-ontia (SrO).
A solution of nitrate of atrontia{;S'rO,if05) maybe used.
229. Neither hydrosulphurie acid nor Jiydroaulphite
of ammonia produce any precipitate in solutions of
sti-ontia.
230. Ammonia and potash behave with solutions of
strontia as with those of baryta ; from concentrated
solutions, potash throws down the white hydrate of
strontia (SrO,HO).
231. Alkaline carbonates also act as with solutions of
baryta (223), carbonate of strontia (SrO,C02) being pro-
duced,
232. (C) Sulphuric acid {B:0,S0.^ and sulphate of soda
(NaOfSOs) throw down a white precipitate of sulphate
of sti'ontia (SrO,80s) immediately, if the solution is not
very dilute, and after standing a short time if it is so ;
in the latter case, the precipitated sulphate is in the
form of minute crystals.
233. (C) Solution of sulphate of lime {CaO,SO^ gives
no immediate precipitate m solutions of sti-ontia, but if
allowed to stand, sulphate of strontia gradually sepa-
rates. Strontia may thus be distinguished from baryta
(225).
234. Phosphate of soda {2]VaO,JTO,PO,) behaves vrith
solutions of strontia as with those of baryta (226).
235. Oxalate of ammonia (JlfS'^0, 0^0^) gives a white
precipitate of oxalate of strontia, in strong solutions,
but not in dilute.
236. The flame of alcohol in which a salt of strontia
is dissolved, or which contains some of the aqueous
=vGoo(^lc
METALS nELONGIHti TO CLASS III. 101
eoliition, assumes a beautiful carmine color, especially
if the mixture is stirred. The color of this fiame should
be compared with that produced when the alcohol con-
tains liiiie (219). "When a salt of etrontia is heated
before the blowpipe, the same carmine color is com-
municated to the flame.
Summary of Class II.
237. Supposing we have in solution a salt of one of
the metals belonging to this class — viz. magnesia, lime,
baryta, or strontia, we should be able, without any
difficulty, by applying a few of the most characteristic
teats, to ascertam which individual of the class it is.
Thus we should find that a solution of hydrosulphato
of ammonia gave no precipitate, and that an alkaline
carbonate gave a white one ; from which we should
infer that the metal belongs to Class II. "We might
then test it with a solution of sulphate of lime, which
would tell us whether baiyta or strontia were present
(225) ; if not, add to a Very dilute solution a little oxa^
late of ammonia, which, if the base were lime, would
throw it down as oxalate (218). If neither of these tests
gave any indication, add phosphate of soda and am-
monia, when if the base is magnesia, the double phos-
phate of ammonia and magnesia is precipitated (206).
Before finally deciding, however, that the base is
either of these, it is always necessary to apply other
confirmatory tests in addition to those just mentioned
(539).
CHAPTER IV.
METALS BELOH&INQ TO CLASS III.
Alumina, Oxide of Chromium, Oxide of Zinc, Protoxide of
Manganese, Protoxide of Iron, Peroxide of Iron, Oxide of
Nkkel, and Oxide of Cobalt.
238. The metals of the third class are distinguished
from those of the first and second, in being precipitated
=vGoo(^lc
102 METALS BELONOINC 10 CLASS III.
from their neutral eolations "by hydrosulphato of am-
monia ; and from those of the fourth class in being un-
affected (with the partial exception of peroxide of iron
{2T8) ) when their solutions, containing a slight excess of
acid, are treated with hydrosulphuric acid.
SECTION I.
Alttmina (AljO,),
A solution of sulphate of alumina {A!^Or^,SSO^+lSAq)
may be used.
239. Sydrosulphurie acid gives no precipitate either
in a neutral or acid solution of alumina.'
240. (C) Hydrosulphate of ammonia {NR^S,jffS) when
added to a neutral solution, ?ives a white precipitate of
hydrate of alumina {AljOajMTO), and hydrosulphuric
acid is at the same time liberated.
241. (0) Ammonia (JVIffg) throws down a bullq? white
gelatinous precipitate, which consiata chiefly of hydrate
of alumina (AIaO,,3H0) with a small admixture of am-
monia, and a basic salt of alumina ; which may be said
to be insoluble in an excess of ammonia, although with
a very large excess, and under peculiar circumstances,
a portion of the precipifeite occasionally redissolvcs.
242. (C) Potash {KG) also gives a precipitate of hy-
drate of alumina, which, like that caused %■ ammonia,
usually contains a little basic salt: it differs from it,
however, in being entirely soluble in an excess of the
precipitant. If the solution ia potash is mixed with
muriate of ammonia {NR^OV), the aluminais again pre-
cipitated.
243. Carbonate of potash {K0,00^ and carbonate of
' In most cases of qualitativo analysis, Iiydrosnlpliuric acid may be
=vGoo(^lc
CHROMIUM. 103
ammonia {^NHtOfiOO^ give a precipitate of hydrate of
alumina, wliicli is insoluble in excess.
^i,Oa,3SOs+3(rO,CO3)+3a'O=AtA,3HO+3CZO,S03)+3CO,.
244. Sulphuric acid and sulphate of soda give no pre-
cipitate in Bolutions of alumina.
245. (C) If a salt containing alumina be moistened
witli a solution of nitrate of cobalt {OoO,NO^, and
heated on charcoal before the blowpipe, it assumes a
beautiful eky-blue color, which is very characteristic, as
no other substance gives so decided a color, though
silica acquires under the same circumstances a tint
somewhat similar, but much leas intense. The blue
color is best seen by daylight, after the mass has cooled,
as by candlelight it appears violet.
SECTION II.
Oxide of OAromium (Grfi^.'
A solution of sulphate of chrome (ft-jOsjSiS'O.,) may be
246. Mydrosulphuric acid produces no precipitate
either in neutral or acid solutions.
247. (C) SydrosulfKate of ammonia {NH,S,HS) when
added to neutral solutions of oxide of chromium, throws
down a dark green precipitate of hydrated, oxide of
chromium (CrjO^iSHO), which is insoluble in excess.
248. (C) Ammonia (NH.^ also produces the same pre-
cipitate (Cr^OjiSHO), a small portion of which redis-
solves in an excess of ammonia, forming a pale pinkish
solution, but is again precipitated when tlie mixture is
boiled.
249. (0) Potash {KO) also throws down the hydrated
' It is remarkable that several of the eomponnda, both soluble and
insolublOj of oxide of chromium, which are green by dajlight, appear
of a reddiah-purple color when seen bj candleliglit. This peculiar form
of dicbroism is seen to great advantage in a solution of the o^ate of
chrome, which is green by daylighl^ but if held between a candle and
the eye, appears purplish crimson. What is still more remarkable is,
that if a creen ooject, anch as a tree or field, be viewed by daylight
through the green solntion, it appears of a bright reddish-pnrple color.
siGooi^le
104 METALS BELONGING TO CLASS III.
oxide, which is soluble in excess, forming a green solu-
tion ; if the alkaline solution be boiled for a length of
time, the hydrated oxide is again precipitated, leaving
the liquid colorless.
250. Carbonate of potash {KO,CO^ gives a dull greeu
precipitate of subeai'bonate of chromium, which redis-
solves in large excess of the precipitant.
251. (0) Oxide of chromium, when heated before the
blowpipe with borax or microcosmic salt, either in the
inner or outer flame, ftises into an emerald-gveen bead.
252. (C) If it is heated with a mixture of nitrate of
potash (KOjNOj) and carbonate of soda (l^'aO,C02), a yel-
low bead of alkaline chromate is formed. Here a por-
tion of the oxygen of the nitric acid combines with the
oxide of chromium (CrjOg), converting it into chromic
acid (CrjOg) or rather (CrOg), which combines with the
potash or soda, foiining an alkaline chromate (KOjCr
O3). If the bead be dissolved in water acidulated vrith
a little nitric acid, the solution will give with salts of
lead a bright yellow precipitate of chromate of lead
(PbO.CrOg) (363).
SECTION III.
Oxide 0/ Zinc (ZnO).
A Golution of sulphate of zinc {ZnOjSO^+T Aq) may be
used.
253. Eydrosulphurie acid (H3), when added to a neu-
tral solution of zinc, causes the precipitation of a por-
tion of it as sulphide (ZnS). This test, however, for
reasons which vrill afterwards appear (541), is usually
applied to solutions containing a slig'ht excess of hy-
drochloric or some other acid. Tor this purpose, acidify
a little of the solution in a test-tube with a drop or two
of hydrochloric acid {HOI) and then test it with hydro-
sulphuric acid ; it will in this case produce no precipitate.
254. (C) Hydrosulphate of ammonia {KH^8,HS) when
added to a neutral or alkfdine solution of zinc, gives a
copious curdy precipitate of sulphide (ZnS), which if
the zuic salt he pure, is white; but if, as is frequently the
=vGoo(^lc
ZINC. 105
case, any iron is present, the precipitate will be more
or lesa colored, owing to the admixture of a little of the
black sulphide of iron (FeS).
ZnO,S0,+NH,S,SS,=Za&+NH,0,S0,+ilS.
255. (C) Ammonia (ifffj) throws down a white gelati-
nous precipitate of hydrated oxide of zinc (ZnO,IIO),
which is readily soluble in excess.
ZiiO, SO,+NH,+ 2HO=ZaO,liO+NSiO, SO^.
If the ammoniaeal solution of the oxide be treated
with bydrosulphuric acid, the white sulphide (ZnS) is
thrown down.
256. (C) Potash [KO) behaves in the same manner as
ammonia, giving a precipitate (ZnO,HO), soluble in
excess. Hydrosulphuric acid throws down the white
sulphide from the potash solution.
257. Carbonate o/j>ofaeA (iTOjCOa) gives a white pre-
cipitate of basic carbonate of zinc {3 (ZuO,HO)-|-2(ZnO,
COj) ), which is insoluble in an excess of the carbonate.
Ammoniaeal salts in solution prevent the formation of
thia precipitate, since they combine with the oxide of
zinc, forming double salts, which are soluble in water.
258. Oarhonate of ammonia (2^11^0,300^) in small
Quantity throws down the basic carbonate of zinc (3
5nO,HO)+2(ZnO,COj)), which readily redissolvea in
an excess of the ammoniaeal salt.
259. iSulphune acid, and sulphate of soda, give no pre-
cipitate in salts of zinc, because the sulphate of zinc is
soluble in water.
260. (C) "When oxide of zinc or any of its salts are
mixed with carbonate of soda, and heated on charcoal
in the inner flame of the blowpipe, the zinc is reduced
to the metallic state, in which condition it is volatilized
by the heat, and reoxidlzed while passing through the
outer flame ; the oside thus produced is in part de-
posited on the charcoal in the form of a pale yellow in-
crustation, which on cooling becomes white {116),
261. (C) If oxide of zinc or its salta be moistenea with
a solution of nitrate of cobalt {GoO,NO^ and heated in
the outer blowpipe flame, the mixture assumes a pale
green color, which is very characteristic. Zinc can in
=vGoo(^lc
106 METALS BELONGIJJG TO Ci,ASS III.
this way be readily distinguislied fi-om other substances,
especially from alumina and magnesia (245, 209).
SECTION IV.
Protoxide of Manrjanese (MnO).
A solution of sulphate of manganese {MnO,SO^-j-l Aq)
may be used.
262. Sydromlphiric acid (HS), when added to an aci-
dified solution (formed by adding a few di'ops of hydro-
chloric acid to a little of the solution in a test-tube),
gives no precipitate. If the solution is neutral, a pai'-
tial precipitation of sulphide (MnS) takes place.
263. (0) HydrosuXphate of ammonia (NH^SySS) gives
in neutral solutions a flesh-colored gelatinous precipi-
tate of sulphide of manganese (MnS), which is insoluble
in excess. If this precipitate be exposed to the air, it
is gradually decomposed, and is converted into the dark
brown hydrated sescLuioxide of (MujO^jSHO), in con-
eec[iienGe of the strong affinity of manganese for oxygen,
which it absorbs from the air.
264. (C) Ammonia (iVS^) throws down a white or pale
. jolored precipitate of hydrated protoxide of manga-
3 {MnO,HO), which if exposed to the air becomes
brown, owing to the formation of the sesquioside
(Mn,0,,2H0), as in the last experiment. 2(MnO,HO)
+o=Mnj03,2HO.
If muriate of ammonia (NH^Ot) is present in the solu-
tion, it prevents the precipitation of the hydrated prot-
oxide ; or, if added subseijuently, redissolves it, owing
to the formation of double salts of ammonia and manga-
nese which are soluble in water. If the ammoniacal
solution be exposed to the air, the brown sesquioxide
is gradually precipitated.
265. Potash (KO) behaves as ammonia in solutions
of manganese: the presence of muriate, of ammonia,
however, does not altogether prevent the precipitation
of the protoxide.
266. Oarbonate of potash {K0,00^ or of ammonia
{2iV!ff^O,3COj) throws down a white precipitate of car-
=vGoo(^lc
bonate of manganese (MnO,COj), wliicli is less prone
to blacken on exposure than the hydrated oxide.
MiiO,SO^+S:0,CO.,=UnO,CO^+EO,SO!,.
267. (C) "When compounds of manganese are mixed
with carbonate of soda (NaO,COa) and heated on pla-
tinum wire iu the outer flame of tlie blowpipe, the
manganese becomes more highly oxidized and is
changed into manganic acid (MnOj) ; this combines with
the soda to form manganate of soda (NaO,Mn03), which
has a characteristic green color. The change is pro-
duced still more rapidly if a little nitrate of potash
(KO,!N'Oc) be added to the mixture.
268. (C) "Wlien mixed with borax (]SraO,2BO5+10Aq)
or mierocosmic salt (NaO,NII,0,HO,P05+8Aq), and
heated in the outer flame of the blowpipe, tlie salts of
manganese form beads of an amethyst purple color,
which is due to the formation of the red oxide (MuaO^).
If the mixture be heated in the inner flame, the color
disappears, owing to the reconversion of the red oxide
into protoxide (MnO) ; this loss of color takes place
most readily witla mierocosmic salt.
SECTION V.
Protoxide of Iron (FgO)-
A solution of protosulphate of iron (FeOjSO^+IAq)
may be used.
269. On account of the sti-ong tendency of the prot-
oxide of iron to absorb oxygen on exposure to the air,
and become eesquioxide, especially in aqueous solu-
tions of its salts, it is difficult to retain the protosalts in
solution without some admixture of sesquioxide ; so that
in testing them, the indications of some of the reagents
are frequently more or less different from those caused
by a pure protosalt. If the solution of a protosalt be
boiled with nitric acid,the protoxide is wholly converted
into peroxide. 6I'eO+]SrO^=SFef,OA-'S>!0^.
270. Sydroaulplmrio acid (HS) produces no precipitate
in acidified solutions of protoxide of iron : a slight pre-
=vGoo(^lc
108 METALS KELOKaiNG TO CLASS III.
cipitation of sulphide (FeS) takes place, however, in
neutral solutions of some of its salts, especially when
the acid with which it is in comhination is a feeble
one.
271. Hydrosulphate of ammonia {NS^S,1IS) when
added to neutral solutions of protoxide of iron, throws
down a black precipitate of sulphide (I'eS), which is
insoluble in excess.
J'eO,S03+JVH,S,fl^fir+£-0=FeS4--WffjO,SOs+HB.
272. (C) Ammonia (iVif^) gives a precipitate of hy-
drated protoxide of iron (FeO,IIO), which is at first
nearly white, but almost immediately becomes greenish.
If this precipitate be exposed to the air, it absorbs oxy-
gen, and is changed into hydrated sesquioxide or per-
oxide (FeaO5,3H0) which has a reddish brown or rust
color. Muriate and some other salts of ammonia, pre-
vent the pi'e cipitation of the protoxide by ammonia,
forming a solution of a double salt of ammonia and iron,
from which the hydrated peroxide is gradually precipi-
tated if exposed to the air.
273. Potash (^0) behaves as ammonia.
274. Carbonate of potash JKO,00^) -prodaaes aTpvecipi-
tate of carbonate of iron (FeO,C09) which is similar in
appearance to the hydrated protoxide (272).
27&. (C) Ferroeyanide of potassium {K^FeCy^-\-ZAqf
throws down in solutions of^ protoxide of iron, a preci-
pitate (KFejSFeCyj) which is at first almost white, but
rapidly changes to pale blue; the color becomes darker
on exposure to the air, owing to the absorption of oxy-
gen, which combines with the potassium and a portion
of the iron, forming at the same time Prussian blue
(Fe^SFeCyj) (282). This change tabes place almost im-
mediately if a little nitric acid or chloride of lime be
added to the mixture.
276. {G) Ferridcyanide of potassium {K^,Fe2,0y^^ ^fO-
duees in solutions of the protosalts of iron, a beautiful
' FerrocjanogBn (PeCyj) ■whicli ia Lara combined with potassium, ia
a hypothetical radical compoaed of iron in a peculiar state of combina-
tiois witli cyanogen (GjN),— -See Pownes' Manual of Chemistry, p. 517.
= Ibid, p. 521.
=vGoo(^lc
PEROXIDE OF IRON. 109
dark blue precipitate, similar in appearance to Prussian
blue, eonaisting of ferridcyanide of iron (FeajFojCy^)-
277. "When heated with borax before the blowpipe,
salts of iron form heads which in the oxidizing flame
become orange, and in the redneing flame green ;
the color being due to the iron in a higher or lower
state of oxidation.
SECTION VI.
Peroxide or Sesquioxidc 0/ Iron (Jejd,).
A solution of the perchloride of iron {Fe^CQ may be
used.
278. Rydrosulphurie aeid (hs) causes in neutral or
acidified solutions of the persalts of iron, a slight preci-
pitation of sulphur, which gives the solution a milky ap-
pearance. This is owing to the decomposition or hy-
arosulphurie acid by the peroxide of ii-on, the hydrogen
combining with a portion of its oxygen, reducing it to
the state of protoxide, while the liberated sulphur is
precipitated in a finely divided state.
F^0„ZS0s+BB=2{Fe0,80s)+H0,S0^->r^.
279. Sydroiulphate of ammonia {NH,S,JIS) separates
the whole of the iron from solutions of its persalts, as
the black sulphide (FeS), the same compound as that
produced in iJie protosalts. The peroxide (Fe^O^ is in
fact first converted into the protoxide IFeO) by the de-
oxidizing affinity of the hydrogen and sulphur in the
hydi'osulphate, so that the subsequent change is the
same as that produced in the protosulphate (271). If
the solution of iron is very dilute, no precipitate ap-
pears at first, but the solution becomes green, and if
allowed to stand a considerable time, the sulphide gra-
dually separates.
280. (C) Ammonia (JVS^ throws down the hydrated
peroxide of iron (FejOj,3HO), in the form of a bulky
reddish-brown precipitate, which is insoluble in an ex-
=vGoo(^lc
110 METALS BELONGINO TO CLASS III.
ceaa of ammonia, and is unaffected by tlie preeence of
ammoniacal salts.
281. Potash {KG) produces tlue same precipitate
(FgjOs,3HO), which ie insoluble in excess.
282. (C) Ferrocyanide of potassium {K^FeCy^-\-ZAq)
produces in solutions of the pei-salts of iron a beautiful
precipitate of eesquiferroeyanide of iron, or Prussian
blue (Fe.SFeCya).
This is an extremely delicate and characteristic test
for the pei-salta of iron, as the precipitate is produced
even in very dilute solutions. In testing for iron with
ferrocyanide of potassium, however, it must be home
in mind that when added to a solution containing much
firee acid, it is partially decomposed, and a little Pinis-
sian blue is formed, even when no iron is present. As
the presence of free alkalies also interferes with the
formation of the blue precipitate, solutions to be tested
with it should be as nearly neutral as possible.
283. Ferridcyanide of potassium {K^jFe^Cy^ produces
no pi-ecipitate with persalts of iron ; it gives, however, a
deep green color to the solution.
284. When heated before the blowpipe, the pei-salts
of iron exhibit the same appearances as those of the
protoxide (277), on account of the facility with which
the two oxides become converted into one another, ac-
cording as they are placed in the oxidizing or the re-
ducing flame.
SECTION VU.
Oxide of Nickel {KiO).
A solution of the sulphate of nicke! {NiO,SO^-T-TAq)
may be used.
285, Hydrosulphuric acid (HS) causes no precipitate
in acidified solutions of nickel ; but if the solution is
neutral, especially if the acid of the salt be a feeble one,
a partial precipitation of sulphide of nickel (NiS) takes
place.
286. HydrosulpTiate of ammonia (]^M^S,1IS) throws
=vGoo(^lc
down, from neutral solutions a black precipitate of sul-
phide (NiS) wbich is very sliglitly soluble in excess,
giving a brownish tint to the solution.
287. (C) Ammonia {NH^ causes a pale green precipi-
tate of hydrated protoxide of nickel (WiOjHO) which
rediseolves when the ammonia is added in excess,
owing to the formation of a double salt of ammonia
and -ai<ikB\ {NHJ),NiO,'2,SO^) which is soluble in water.
If potash {KO) be added to the ammoniacal solution, it
reprecipitates the hydrated protoxide of nickel. The
presence of ammoniacal salts in the nickel solution
prevents the precipitation by ammonia.
288. Potash {KO) also mrows down the hydrated
oxide of nickel (NiO,HO), which is insoluble in an ex-
cess of potash.
289. Oarionate of potash {K0,00^ gives a precipitate
of carbonate of nickel (NtO,COj), together with a little
hydrated oxide, insoluble in. excess.
290. Carbonate of ammonia {2NHfi,ZC0^ produces
the same precipitate, which redissolves in excess.
291. (C) Cyanide of potassium {KGy)' throws down a
precipitate of cyanide of nickel (!NiCy), which has a yel-
lowish green color : it redissolves in an excess of the
alkaline cyanide, forming a dull yellow solution of the
double cyanide of nick^ and potassium {NiCy,KGy),
from which the cyanide of nickel is again precipitated
on the addition of dilute sulphuric or hydrochloric aeid.
If the aeid mixture be boiled, the precipitate again
dissolves, forming a solution of sulphate or chloride of
nickel.
292. (C) When heated with carbonate of soda (WaO,
CO,) or borax (NaO,2BO3+10Aq) in the inner flame of
the blowpipe, the compounds of nickel are reduced to
the metallic state, forming gray-colored beads, owing
to the minutely-divided metal being held in suspension
by the melted flux : if the latter be dissolved out with
water, the precipitated metal will be found to be mag-
netic. In the outer flame with boi-ax, the color of the
=vGoo(^lc
112 METALS BELONGING TO CLASS III.
bead is usually violet while hot, becoming brown or
yellow on cooling. With microeosmic salt, the bead le
reddish while hot, but loses the color more or less en-
tirely when cold.
SECTION VIII.
Oxlih of Cobalt (OoO).
A solution of the nitrate {OoO,NO^-\-QAq) or chloride
{OoOl) may be used.
293. Uydrosulphuric acid (l£S) gives in acidified solu-
tions no precipitate. If the solution is neutral, a slight
precipitation of the black sulphide of cobalt (CoS) takes
place.
294. Eydrosulphate of ammonia {NH^S,SS) throws
down from neutral solutions a copious black precipitate
of the sulphide (CoS), which is insoluble in excess, and
also in hydrochloric acid.
2 CoCl+NHS,BS=2Go-S,+NH, Cl+HCl.
295. (C) Potash [KO) throws down a precipitate of a
blue color, consistmg of basic salts of cobalt, which
soon becomes gi'eenish if exposed to the air, owing to
the absorption of oxygen ; and lastly, especially if the
solution be boiled, dirty red, owing to the formation of
hydrated oxide of cobalt (CoO,HO). The precipitate
is insoluble in excess of potash.
296. (C) Ammonia [NR^ behaves as potash, but the
precipitate readily redissolves in an excess, forming
double salts of cobalt and ammonia, which are soluble
in water. If the ammoniacal solution is exposed to the
air, it gradually becomes darker, owing to the absorp-
tion of oxygen, and formation of peroxide of cobalt
297. Carbonate of potash {K0,00^ produces a pale
pink precipitate, which is a mixture of carbonate of
cobalt (CoO.COj) and hydrated oxide (CoO,HO).
298. (C) Cyanide of potassium {KCy) when added to a
solution of cobalt, especially when a slight excess of
hydrochloric acid is present, gives a pale brown pre-
cipitate of cyanide of cobalt (CoOy), which, when heated
=vGoo(^lc
METALS BELONGING TO CLASS IV. 113
with an excess of cyanide of potaseium, readily redis-
solves, forming a soluble douMe cyanide of cobalt and
potassium {K^Co^Cy^, The addition of sulphuric acid
causes no precipitate in this solution (291).
299. (C) The compounds of cobalt, when fused with
borax (NaOtSBOj+lOAq), either in the inner or outer
flame of the blowpipe, iorai. beads of an intense blue
color, or if there is much cobalt present, neai'ly black ;
this appearance is very characteristic. Mieroeosmic salt
acts with cobalt in a similar manner, but in a less
marked degree. When mixed with carbonate of soda,
and heated on charcoal in the deoxidizing flame, oxide
of cobalt is reduced to the metallic state, forming a
magnetic powder.
CHAPTER V.
METALS BELONGING XO CLASS IV.
Arsenic (of which there are two oxides, hoth havi-ng acid proper-
ties — namely, Arseniovs Acid and Arsenic Acid}, Oxide of
Antimony, Protoxide of Mercury, Peroxide of Mercury, Oxide
of Lead, Oxide of Oopper, Oxide of Silver, Protoxide of Tin,
Peroxide of 3V», and Oxide of Bismuth,
300, These metals are distinguished from those of
the three preceding classes, hy being precipitated from
their acidified solutions when treated with hydrosul-
phuric acid. It is remarkable that nearly all the metals
whose compounds are most eminently poisonous belong
to this class, and as these are the most important, especi-
ally to the medical student, they are placed first, and de-
scribed in the order of their importance. The oxides
of arsenic, though possessing acid properties, and con-
sequently belonging strictly to the chapter on acids,
have so many peculiarities in common with this class
of oxides, that I have included them in it.
=vGoo(^lc
BLONGIMG TO CIAS
Arsenious Acid or Oxide of Arsenic (AsO,).
301. On account of tlie highly poisonous nature of
arsenic, great care should be taken, in the following ex-
periments, not to use more than is absolutely neceasaiy
to exhibit its peculiarities. In all these experiments
(except those of solution), a fragment the size of a small
pin's head is quite sufficient. There is also another ad-
vantage in using such small quantities — namely, that in
most medico-legal investigations, the quantity to be
looked for is equally or even more minute, and it is
consequently very important that the student should
make himselffamiliar with the appearances which would,
under these eireumstanees, present themselves.
301 a. (C) The following experiment should only be
made either in the open air or in a well-ventilated room,
on account of the poisonous properties of the arsenic
vapor. If a small fragment of arsenious acid be heated
on charcoal before the blowpipe, it is wholly volatilized,
and a smell of garlic will generally be perceptible, es-
pecially when it is subjected to the reducing flame.
Both metallic arsenic and its oxide are volatile when
heated, but the fumes of the latter have no smell. The
odor of arsenic vapor appears to be due to the metal
while undergoing oxidation, and may be caused perhaps
by the formation of a lower oxide than the arsenious
acid ; it is always observable when metallic arsenic is
volatilized in contact with the air.
302. (C) Place a fragment of arsenious acid in a nar-
row tube (102), and apply a gentle heat with the blow-
pipe. It sublimes without decomposition, and con-
denses in the cool part of the tube, in the form of minute
sparkling octohedral crystals (Fig. 69), which should be
examined with a lens, as they arehigbly characteristic.
The size and regularity of the ciystals depend on the
slowness with which the vapor is condensed. If the
snrface of the glass on which the condensation takes
place is quite cold, the sublimate is often amorphous,
»Si may be seen by holding a piece of cold glass in the
=vGoo(^lc
fames given off by a little arseiiious aciil, lieat^J <
charcoal (301). The best way
m<
to obtain large and well-defined
cryetals, ia to ^ut a few grains v-^mr~.
Of aTseniou8 acid at the bottom ig ^^ ^^J«
of a common test-tube, and ^a ^A ^^
allow it to stand on a tolerably ^^'^w^^S?
hot eand-bath for half an hour, A'^-A^ M. /\
the lower part only of the tube ^'^ ^\eS^
being embedded m the sand. ^ WtCp^
If a small strip of flat glasa be ^^ m^Y^
also placed inside the tube, a "^ w
portion of the acid will con- crystals wAtMnioiieAo.
dense upon its surface ; thus furnishing a convenient
specimen for microscopic examination.
303. (C) Mix a little oxide of arsenic (AsOs) with
black flux (751), which if at all damp should be previ-
ously dried on the eand-bath, and heat a „, . .„
little of the mixture in a clean tube before
the blowpipe. The arsenious acid ia de-
oxidized by the carbon of the flux, and the
metallic arsenic thus reduced sublimes, and
condenses in the upper part of the tube,
forming a more or less brilliant metallic
crust, a (Fig. 70). AsO.+SC=As+3GO.
If heat be now applied to the sublimate,
it will again volatilize, and if any of the
vapor escapes from the tube, it may be re- cmst
cognized by its characteristic odor of garlic
(301 a).
304. (C) Cut off by means of a file, the portion of the
tube containing the crust, break it into fragments, and
place some of them in another tube. Sublime the
arsenic bacljiwarda and forwards two or three times in
the tube, and observe the gradual conversion of the
metal into crystalline arsenious acid, which is formed
by the action of the atmospheric oxygen contained in
the tube.
305. Boil a few grains of arsenious acid with water
(in which it is sparmgly soluble), in a flask: filter the
solution from the undissolved portion, and retain it for
testing.
=vGoo(^lc
116 METALB BELOSOING TO CLASS IV.
306. Repeat the last expeiiment, ■witli the addition
of a few drops of solution of potash {KO) to the water,
and observe the increased solubility of the arsenic,
owing to the fonnationof arseniteof potash(/ir(?,J.803).
Retain the solution for testing.
307. (C) Hydrosulfhuric acid (HS), when passed
through a solution of arsenioua acid or of a neutral
arsenite (699), causes a slow and gradual precipitation
of tersulphide of arsenic, or sulpharsenious acid (AsS^),
which it will he observed is analogous in composition to
the oxide (AsOj), three equivalents of sulphur being sub-
stituted for three equivalents of oxygen. AsO^-{-Q^^=
AsSj+S^O.
If the solution be acidified, however, with a few drops
of hydrochloric acid, a much more rapid and complete
decomposition takes place ; and if the gas be passed
through the solution for some time, a complete separa-
tion of the arsenic may in this way be eft'ected. The
sulphide of arsenic thus formed has a bright light-yellow
color; it is insoluble or nearly so in dilute hydrochloric
acid, but readily soluble in solutions of the alkalies or
their carbonates. Boiling nitric acid [NO^ also dis-
solves it with decomposition, foiming sulphuric and
arsenic acids.
AsSs+ 5AfOs=^s05+3S03-|-5NOi,.
308. (C) Filter the yellow sulphide formed in the last
experiment, and dry a portion of it at a gentle heat on
the sand-bath : mix a little of it with black flux (308),
heat it in a tube, and observe the formation of a metal-
lic crust of ai-senie. AsS3+3(KO,COa)-H2C=AB+3EB
-j-4C05-}-CO.
809. Sydrosulphate of ammonia {NM^S,HS), when
added to a neutral solution of an areenite, also causes
the foiTaation of the yellow sulphide {AsSj which how-
ever does not precipitate, but remains dissolved as
the double sulphide of arsenic and ammonia {NS^SjAs
S^. If an acid be added in excess to the mixture, the
sulphide of arsenic is immediately precipitated, of a
somewhat lighter color than that thrown down by hy-
drosulphnric acid, owing to the admixture of a little
sulphur derived from the hydrosulphate of ammonia
(440).
=vGoo(^lc
ARSENIC. 117
310. (0) Nitrate {AgO.lSO-^ or ammmio-nitrate {AgO,
2]Srff^,]Si 0^ of silver, throws down in neutral solutions of
arsenic, a canary-colored precipitate of areenite of silver
(2AgO,A805), which is soluble both in ammonia and
nitric acid. It must be remembered that phosphate of
Boda also produces, with nitrate of silver, a similar pre-
cipitate, which ie ec^ually soluble in nitric acid and am-
monia (378).
311. (C) Sulphate (GuO,SO^, or ammonio-aulphate
(CtiO,2Nffg,MO,SOg) of copper, produces in neutral ar-
senical solutions, a delicate green precipitate of areenite
of copper (2CuO, AsOj), which dissolves readily both in
ammonia and nitric acid, forming a rich blue solution.
It must be borne in mind, in employing this test, that a
similar precipitate is produced when the solution of
copper IS added to a liquid containing decoction of
onions and some other vegetable substances, though
no arsenic may be present.
Marsh's Test.
312. (C) It is well known that when zinc is treated
with dilute. sulphuric acid, it is oxidized at the expense
of the oxygen of the water, and hydrogen gas is given
off (12). n in addition to the zinc and dilute sulphuric
acid, either of the oxides of arsenic are present, the zinc
abstracts oxygen from them as well as from the water ;
and the metallic arsenic thus formed, combines, at the
moment of its liberation, with some of the hydrogen
simultaneously produced, and forms a gaseous com-
pound called arseniuretted hydrogen (AsH^), which passes
oft' mixed with the excess of hydrogen.'
^sO,-|-G2n+e(irO,S03)=6(Z«0,SOs)-l-ABll3+3.HO.
Kow if this arseniuretted hydrogen is heated strongly
either by burning in the air, or by passing through a
red-hot tube, it is decomposed, and metallic arseiiie or
its oxide ia deposited in the solid state, while the libe-
rated hydrogen passes off.
' It must be borne in mind fbat this gas, like most of tlie oilier coni-
pounds of arsenic, is Mghly poisonous ; so tliat the experiment should
never be performed in a close room, but in the opea air or in a weli-
ventilated apartment.
siGooi^le
diminish the aperture.
lift MGTALS BELONGING TO CLASS IV.
313. Several forma of apparatus have heen contrived
for making use of this property in the detection of
arsenic ; — of these the following is in pi-actice the most
convenient : The bottle a (Fig. 71) should be capable
of containing six or eight
ounces of water, and is
connected hy means of a
peifomted corlc with the
tubes 6andc, which should
be about half an inch in
diameter ; to the latter is
attached by means of a
cork, the tube d, which
should be made of hai'd
German glass, bent at a
right angle, having the
end e drawn off so as to
A few fi'agments of zinc are
i in the bottle, and when the cork with its tubes
IS attached, pour a little dilute sulphuric acid down the
tube h, which should reach nearly to the bottom of the
bottle, and allow the gas (hydrogen) to be given off for
five minutes." Then heat the narrow tube with a spirit
lamp at the point d, and observe carefully whether
there is any deposit produced inside the tube : this pre-
caution is necessary, since some kinds of sulphuric acid,
and also of zinc, contain traces of arsenic. If no stain
is produced, it may be assumed that the materials are
pure.
314. The solution containing (or suspected to con-
tain) arsenic, acidified with a few drops of hydrochloric
acid, is now introduced through the tube h, the heat
being still applied to the nan-ow tube at d, as before.
If arsenic is present in the liquid, it will cause the for-
mation of arseniuretted hydrogen ; which on passing
through the heated tube is decomposed, and the arsenic
deposited, not exactly at the heated point, but a quarter
' The reason why it is not safe to apply the heat at once, is, that a
mixture of hytlrogen and common air is highly explosive (11), 30 that
it ia necessary to allow time for the whole of the common air to be ex-
pelled by the hydrogen ; as otherwise serious injury taight be caused by
an explosion of the mixed gases.
siGooi^le
AilSENIC. 119
or half au incli beyond, in consequence of its volati-
lity. The metallic cruatthusformedmay be volatilized
backwards and forwards in the tube, by heating it -with
the flame of a spirit lamp.
315. (C) The arsenical crust may also be obtained in
another way — namely, by lighting the jet of gas as it
issues from the aperture e, and holding in the flame a
small porcelain plate (for which purpose the lid of a
porcelain crucible answers extremely well), when the
metallic arsenic will be deposited in the form of a dark
shining spot : if the porcelain plate be raised a little, so as
to be out of the flame, the arsenic in the state of vapor
becomes oxidized while passing through the air, and a
white deposit of arsenious acid is formed on the plate.
By applying heat to the dark spots, they are readily
volatilized, and the fumes will be found to have the
characteristic odor of garlic.
A few of these spots should be retained for further
examination, and for comparison with those of anti-
mony (320).
316. Hold a short test-tube with the mouth down-
wards, iust above the apex
of the flame (Fig. 72) for a Fig. 72.
few momenta, so as to col-
lect some of the arsenious
acid formed by the oxida^
tion of the arsenic vapor,
and reseive the tube for
comparison with antimony
317. Marsh's teat as just \f^ ' ' —
described is so exti'emely \
delicate, that it is capable
of detecting arsenic in a solution containing the mil-
lionth of its weight of the acid, and may be considered
the moat conclusive test which we possess. It is how-
ever liable to this objection, which is, in practice, easily
overcome. It is found that antimony, when present in
a mixture of zinc and dilute sulphuric acid, combines
with the liberated hydrogen, precisely in the same way
aa arsenic, forming an analogous compound called an-
timoniuretted hydrogen (SbH^ ; which when, heated, is
J
siGooi^le
120 METALS BELONGING TO CLASS IV.
decomposed, and the metallic antimony is at the eame
time deposited. Hence it is extremely important that
we should be able to distinguish accurately between
them, as otherwise we should not be sure whether the
crust produced by Marsh's test were due to arsenic
or antimony. One or two experiments are generally
sufficient to enable us to do this,
S18. For the purpose of eomparieon, empty the zinc
and sulphuric acid from the bottle used for tho arsenic
experiments (313), and substitute fresh zinc and acid.
"When the gas has been coming off about five minutes
(note to 313), pour in a few drops of a solution of the
double tartrate of antimony and potash {KO,SbO^,O^St
0,ii+2J.j) and apply heat as before at the point d. A
crust of antimony will be deposited at the heated point,
and not, aa in the ease of arsenic, at a little distance
from it ; this is owins to the antimony being less vola-
tile than arsenic, and it will be found impossible to
volatilize it by the heat of a common spirit lamp. In
this respect, therefore, we are enabled in some measure
to judge whether the stain is due to antimony or ar-
senic.
319. Light the jet of gas that issues from the aper-
ture e as in (315), and hold over the flame a porcelain
plate as before : a deposit of metallic antimony will be
formed similar to that of arsenic, but blacker and less
shining.
Prepare a few of these spots for comparison with
those of arsenic formed in (315).
820. (0) Apply the heat of a spirit lamp to one of
each kind of spot, and observe the superior volatility of
the arsenic, and the garlic odor of ita vapor.
321. (0) Moisten one of each kind of spot with hy-
drosulphate of ammonia {NH^S^HS) which for this pur-
pose should contain an excess of sulphur (710), and ob-
serve that the antimony is immediately dissolved, while
the arsenic remains nearly unaffected for a considerable
length of time. This is a most valuable means of dis-
tinguishing between them, and was first observed by
Dr. Guy.
322. (C) If the spots be moistened with a solution of
=vGoo(^lc
chloride of lime (CaOC/), tbeai-eenic will dissolve, while
the aatimony will remain unaffected.
323. (C) The following may also be taken as a distin-
guishing test between the arsenic and antimony when
Marsh's process isfoUowed. Light the jetofgasissuing
from the apparatus, and hold over it a short tube as in
(316), so as to collect a little of the oxide of antimony
(SbOj) formed by the oxidation of the antimonial vapor.
Compare the sublimate thus formed, with that of ar-
seniotts acid, and observe the more crystalline appear-
ance of the latter. When the tube ie cold, pour in a
little water, and treat the arsenious acid in the same
way : observe the latter dissolves in the water, while the
oxide of antimony remains insoluble. The solution of
arsenious acid may then be divided into three portions
and tested ; the first with hydrosulphuno acid (307) ; the
second with ammonio-nitrate of silver (310) ; ana the third
with ammonio- sulphate of copper (311).
These experiments, in conjunction with the other
liquid tests, will be found sufficient to prevent the pos-
sibility of error in the use of Marsh's teat.
Beinsch's Test.
324. (G) This test is founded on the circumstance that
when a metal, such as copper, is heated in a solution of
another metal more electro-negative than itself, the lat-
ter is sepai'ated in the metallic state, and deposited on
the surface of the former, which is at the same time dis-
solved in atomic proportion. A little of the solution
containing arsenic is acidified with a few drops of hy-
di'ochloric acid, and boiled in a test-tube with a strip or
two of clean copper foil : the arsenic, being more electro-
negative than the copper, is deposited on the surface of
the foil, and the whole is in this way separated from the
solution.
325. The appeai-ance of a metallic deposit on the cop-
per is not, however, necessarily a proof of the presence
of arsenic, since other metals (as bismuth, silver, mer-
cury, or antimony) would produce a similar incrustation,
being all more electro-negative than copper. Arsenic,
=vGoo(^lc
122 METALS BELONOISG TO CLASS IV,
however, is readily distinguished from any of these iu
the following manner.
Talie the copper efcripa out of the solution, and dry
them cautiously between folds of filteringpaper, or with
a very gentle heat: place them in a clean dry test-tube,
and apply heat, when the arsenic will be volatilized, and,
becoming oxidized by the air contained in the tube,
will form a crystalline sublimate in the upper part
(302).
Had the deposit on the copper been either of the
other metals (with the possible exception of antimony
and mercury), it would not have been volatilized when
heated: if it were mercury, minute globules of the metal
would have condensed in the cool part of the tube :
and had it been antimony, a higher degree of heat
would have been necessary to sublime it ; — the subli-
mate would have been white and amoii^hous instead of
crystalline ; — and when treated with water, would prove
insoluble, while the ai-senious acid would dissolve, and
the solution, on being tested, would show the presence
of arsenic'
This excellent test may be considei'ed almost equal
to Marsh's botli in point of delicacy and freedom from
sources of error.
Ari'enic Acid
326, Mix a little araenious acid with nitre (KOjNO^)
and heat it in a tube. The nitric acid of the nitre
gives up a portion of its oxygen to the arsenic, forming
arsenic acid (AsOj).
2Aa0s+2NOs=2AsO6+NO5+NOi.
Dissolve the fused mass in water, neutralize the solu-
tion with dilute nitric acid, and test it with nitrate of
silver {AgO,NO^ : a reddish-brown precipitate of ar-
seniate of silver (SAgOjAsO,) is thrown down, which is
soluble in nitric acid, and also in ammonia.
' As the hydrochloric acid of commerce frequeally contains traces of
arsenic, it is always absolutely necessary, in medico-legal investigations,
to ascertaiu whether the acid employed is perfectly free from it ; this is
easily done by boiling a little of the acid, dilated with distilled water, in
a test-tube with copper foil, which aiiould then be dried and heated in a
cle:ui tube, when if arsenic is present it will snblinie.
=vGoo(^lc
AN TIM MY. 123
Detection of Arsenic in Organic Mixtures.
327. la most cases of medieo-legalinveatigation as to
the px'esence of arsenic, we liave to deal wiBi mixtures
containing a considerable quantity of organic matter
both liquid and solid, which seriously interferes with
the action of the tests. Several methods have been
employed to get rid of these matters, but the following
is perhaps the simplest, and at the same time the moat
etiectual : it is a modification of Eeinseh's test.
If the organic mixture suspected to contain arsenic
is fluid, it IS, previous to filtration, boiled for half an
hour with about one-tenth of its bulk of strong hydro-
chloric acid, the purity of which should of course be as-
certained (see note to 325) ; and if necessary, filtered from
any solid matter. It is then boiled with copper foil,
when the arsenic, if present, is deposited on the copper,
which must be subsequently heated in a tube according
to the directions already given (325).
If the matter to be examined is solid, it is treated
with dilute hydrochloric acid containing about one-
tenth of the strong acid, boiled for half an hour or an
hour, filtered if necessary, and then boiled with copper
as before.
If the arsenic is present only in very small quantity,
a quarter of an hour may elapse before the deposition
takes place ; and if it does not then appear, the boiling
should be continued half an hour or even longer,
before we finally conclude that no arsenic is present.
For further particulars on this subject, the student
may refer to Dr. Christison's Treatise on Poisons, or to
Dr. Guy's excellent work on Forensic Medicine.
Oxide of Antiraowj (StO,),
For the liquid teste, a solution of the double tartrate of
antimony and potash {KO,ShO^,O^B:j}^^^-p.Aq), or of
chloride of antimony (.SJCTj) in hydrochloric acid, may
be used.
=vGoo(^lc
124 METALS BELONGIKG TO CLASS IV,
328. (C) Heat a small erj'stal of the double tartrate in
a tube, aud observe tbat it decrepitates aud blackens,
owing to the decomposition of the vegetable acid ^0,
HjOio) and the consequent deposition of charcoal. Ignite
the residue, which consists of charcoal, carbonate of
potash, and oxide of antimony, on charcoal in the de-
oxidizing flame of the blowpipe, when the oxide of an-
timony will be reduced, and small globules of the metal
vriil appear: a portion of the reduced metal volati-
lizes with the beat, becomes reoxidized while pass-
ing through the outer flame, and the oxide thus pro-
duced is deposited on the charcoal, either in the form
of a white powder or in crystalline needles.
329. (C) w'hen a stream of hydrosulphuric aoid(liS)
is passed through a solution of antimony acidified with
a little hydrochloric acid, an orange-red precipitate of
sulphide ofantimony(Sb83)isproduced,wmch is soluble
in alkaline solution, and difficultly bo in hot hydro-
chloric acid. If the solution is neutral, the precipitation
takes place but imperfectly, and in alkaline solutions
not at all,
380. Mydroaulphate of ammonia (NM^SyRS) when
added in a small quantity, gives an orange precipitate
of sulphide (SbS,), which rediesoives in an excess of the
hydrosulphate. If the alkaline solution tbusfoi-medbe
neutralized with an acid, the sulphide is reprecipitated,
mixed with a little sulphur (309).
331. Ammonia {NE^, Potash (KO), or their carbo-
nates, throw down from solutions of chloride of anti-
mony {SbOl^), but not in solutions of the double tartrate,
a white precipitate of oxide of antimony (SbOj), which
is soluble in excess of potash, but insoluble or nearly
so in the other solutions.
332. (C) If a solution of chloride of antimony in hy-
drochloric acid be diluted with a good deal of water, a
white precipitate of basic oxiehloride of antimony (Sb
Cl3,5Sb03) 13 produced, which if allowed to stand for
some time, becomes crystalline.
A similar precipitate is formed under the same cir-
cumstances in solutions of bismuth (394): the bismuth
precipitate may be distinguished by its insolubility in
=vGoo(^lc
MBRCORT. 125
tartaric acid (230,(7^7/^0,5), in which tho oxichloncle of
antimony ip soluble.
333. A piece of clean zinc or copper cauaea a precipi-
tation of antimony in the metallic state (324).
334. (C) "When oxide' of antimony is present in a
mixture of zinc and dilute sulphuric acid, the antimony
is reduced and combiaes with the hydrogen, as already
described in the case of arsenic (312), forming auti-
moniuretted hydrogen (SbH,), which is decomposed
when burnt, or when passed through a heated tube, with
the formation of a deposit of metallic antimony. This
experiment has already been described (318).
For the methods of distingaishing between antimony
and arsenic, see (317) to (323).
SECTION III.
Frotoxide of Mercury (HgO).
For the first five experiments, calomel (HgCl) may be
used ; for the reat, a solution of the protonitrate
{HgO,NO^) may be taken.
335. (C) Heat a small fragment of calomel (not larger
than a small pin's head) in a clean tube. It becomes
pale yellow, and, being volatile, it sublimes and con-
denses in the upper part of the tube ; on cooling,
the color disappears. ^'^- ''^^
336. (C) Dry a small piece of carbonate of soda f^
(NaOjCOj) either in a tube or on a piece of char-
coal ; mix with it a little calomel, and put the
mixture into a tube, a, (Fig. 73) ; then cover it
with a layer of carbonate of soda in powder,
about a quarter of an inch deep, 6, and apply
heat. The calomel is decomposed, and minute
globules of metallic mercury condense in the 11?°
cool part of the tube at e.
HgCI+Na0,00s=NaCl+ifj/-i-O+CO,.
337. Boil 3. little calomel with distilled water in a
test-tube ; pour ofl' the water into another tube, and test
it with hydrosulphate of ammonia (340) ; no effect is
=vGoo(^lc
126 METALS BELONGING TO CLASS IV.
produced, proving that the calomel is insoluble in
water.
338. (0) Potash {KO) or ammonia [NH^) poured on the
calomel, decomposea it, turning it black, owing to the
formation of the protoxide (H^O). Chloride of potas-
sium {KCtj is at the Bame time formed.
HgCl+^0=HgO+-E:Oi.
S39. (C) Boil a little calomel in fine powder witli a
solution oi protochhride of tin{SnOl): after some little
time the mercury is reduced to the metallic state, owing
to the strong affinity which the protochloride of tin
has for as additional equivalent of chlorine, which con-
verts it into the bichloride {SnO^). 'HgC\+SnCl=Mg-{-
SnOl,.
340. (C) When a solution, either neutral or acid, con-
taining protoxide of mercury, is treated with hydrosul-
phuric aeid (HB) or hi/drosulphate of ammonia (NS^S,
"BiS), a blacs precipitate of protosulphide of mercuiy
(HgS) is thrown down, which is insoluble in dilute acids
and also in excess of the hydrosulphate : it is soluble
however, in ac[ua regia. Eg 0,_NO^A-^Q^'SgSA-SO,NO,.
If the precipitate, after being dried, be heated alone
in a tube, it is decomposed into metallic mercury and
the peraulpbide (HgSA SHgS-HgS.-j-iT^.
341. Ammonia (S'll^ gives a black precipitate, con-
sisting of a basic double salt of mercui-y and ammonia
(!N'H3,3HgO,N05), which is insoluble in excess.
342. Potash {KO) produces a black precipitate of
protoxide of mercuiy (HgO), which is insoluble in ex-
cess.
3gO,NO-,+KO=RgO +KO,NO^
343. (C) JHydroahloric aeid (HOl), or a solution of
chloride of sodium {NaCT), throws down a white precipi-
tate of protochloride (calomel, HgCl), which is insoluble
H'j 0,KO.^+Na Ol=B.gCl+Na 0,1^0^.
344. (C) Place a strip of clean copper in tlie mer-
curial solution, and observe the deposition of metallic
mercury (324). SgO,]!\W^+C\x^Eg+Cv,0,JVO,.
If the stain be rubbed, it will become bright and
=vGoo(^lc
silvery. Dry the atained copper, place it in a dry tube,
and apply beat ; the mercury subiimce, and condensea
in minute globules in the upper part of the tube.
SECTION IV.
Peroxide of Mercury (HgOj).
The perchloride of mercury or corrosive sublimate
(HgCy, either solid or in solution, may be used.
345. (C) Heat a small fragment of the perchloiide in
a tube ; it fuses, boils, and sublimes into the upper part
of the tube. If the experiment be made on charcoal,
the whole is volatilized.
346. (C) Eepeat the experiment described in (336)
using the perchloride instead of calomel ; metallic mer-
cury sublimes in both cases.
347. Boil a little with water, in which it readily dis-
solves, thus differing from the protochloride.
348. (0) Test a solution of the perchloride with a small
quantity of hydromlphurw acid (HS). A white precipi-
tate is hrst formed, which on the addition of more of the
Erecipitant, gradually becomes dai'ker and ultimately
lack. This change of color is owing to the forma^
tion first of a double compouud of sulphide and chloride
of mercury (SH^^jjIIgClj), which is white ; and when
the hydrosulphurie acid is added in excess, the whole
of the mercury is converted into the black persulphide
(HgSj). The precipitate is insoluble in hydrochloric
and nitric Eicids, but is readily decomposed by ac[ua
regia, and again converted into the perchloride.
If the persulphide be dried and cautiously sublimed
in a tube, it is deposited, without decomposition, in the
foiTQ of dark red crystals of cinnabar.
349. (C) Bi/drosulphate of ammonia (NEfSjffS) be-
haves in the same way as hydrosulphurie acid.
350. Ammonia (^.S^) throws down a white precipi-
tate, which consists of a double compound of perchloride
and amidide of mercury (HgClajHgSNHj).'
' The amidides or amides, are componnda of a metal with amidosen,
which is a hypothetical salt radical, supposed to consist of NHj i 't h^^i
siGooi^le
12e METALS 8EL0NGIKG TO CLASS IV.
851. (C) Potash {KO) gives a yellow precipitate of
liydrated peroxide of mercury (Ha;0j,3H0) which ia in-
soluble in excess. If ammoniacal salts are present, the
precipitate formed by potash is white, and consists of
the same compound as that thrown down by ammonia
(350).
352. (0) When protooMoride of tin (SnOl) is added in
small quantity the perchloride is reduced to the state of
protoehloride (HgCl), which separates as a white preci-
pitate. If the salt of tin be added in excess, and the
mixture boiled, the mercury is reduced to the metallic
state (339).
353. (C) Iodide of potassium (S/) causes a most beau-
tiful red precipitate of periodide of mercury (HgLj),
which surpasses even vermilion in brilliancy of color.
It is readily soluble in an excess of either of the solu-
tions.
Eg Cl^+2KI=B.gli+2KCl.
354. (0) A strip of clean metallic copper precipitates
mercury in tlie metallic state (344),
. 355. Heat a small fragment of the red peroxide of
mercury (HgOj) gently in a small tube, and observe
that it becomes much darker in color when hot, and
reasBumes its former tint on cooling. If the heat be
increased to a little below redness, the oxide is decom-
posed into metallic mercury and oxygen, when the
metal condenses in minute globules in the cool part of
the tube, and the oxygen may he detected by introduc-
ing a glowing match (109).
SECTION V.
Oxide of Lead (PbO).
A ao!utioa of the acetate {PhO,0,Bfir^-^ZAq) ox the
nitrate (PhO,NO^) may be used.
356. (C) When a fragment of any of the salts of lead
(except the phosphate (412) ) is heated on charcoal in the
however, never been obtained in an insulated form. SeeFownea' Manual
of Cliemistry, p. 205.
=vGoo(^lc
LEAD. 129
inner flame of the blowpipe, a globule of metallic lead
is formed, which is usually surrounded by a little de-
posit of the yellow oxide (PbO). The metallic globule
will be found to be soft and malleable. In the oxidiz-
ing flame, oxide of lead forms with borax and micro-
cosmic salt, yellowish beads, which become nearly
colorless on cooling.
357. Hydrosulphurio aeid (HS) throws down in eolu-
tiona containing lead, either neutral or slightly acidified,
a dense black precipitate of sulphide of lead (PbS).'
Pb 0,i>rOs-|-HS=PbS+ ffOiVOj.
If the sulphide be boiled with strong nitric aeid, it is
fradually converted into the insoluble sulphate (PbO,
Oj), both metal and sulphur becoming oxidized at the
expense of the nitric acid.
358. Mt/drosulphate of ammonia (]^H^S,ffS) produces
the same effect.
359. Ammonia (NIT^) and Potash {KO) throw down
white precipitates, consisting of oxide of lead in combi-
nation witli a small quantity of aeid (basic salts).
Ammonia produces scarcely any precipitate in a solu-
tion of acetate of lead, owing to the formation of the
subacetate (gPSOjC^^;^^), which is soluble.
360. Carbonate of potash {K0,00^) give6 a white pre-
cipitate of carbonate of lead (PbO,C02), which is in-
soluble in excess.
361. (C) Salphurio acid {EO,SO^ or a solution of sul-
phate of soda {NaO,SO^, produces a white precipitate
of sulphate of lead (PbO,80,}, which is insoluble or
nearly so in acids, but soluble in potash, and also in
acetate of ammonia {NHfi,O^Hfi^.
Pb o,NO-,+m o,so,=?hom,+N<i o,no^.
If the precipitate be moistened with a solution of hy-
drosulphate ofammonia, it is instantly blackened, owing
to the formation of sulphide of lead (PbS) : it is distin-
guished in this way irom the insoluble sulphates of
baryta and atrontia.
362. (C) Bydrooklorie acid (BOl), or a solution of
chloride of sodium (NaOl), throws down a white and
' Under some peculiar circamstances, Ibis reagent throws down a red
precipitate in solutJoiiH of lead (see 3G5).
=vGoo(^lc
130 METALS BELONGING TO CLASS IV.
often ci-ystalline precipitate of chloride of lead (PbCi).
If the solution with the precipitate be boiled, a portion
of the chloride dissolves, and is deposited again on
cooling, in the form of needle-shaped crystals. If the
solution of lead is dilute, the chloride does not precipi-
tate, as it is somewhat soluble in water.
FbO,NO,+BCl^FbC\+HO,N0i.
The chloride of lead is unaffected by an excess of ain-
monia.
363. (C) Chromate of potash (KO,CrO^) gives a fine
yellow precipitate of chromate of lead (PbO,CrOs) which
is insoluble m dilute acids, but soluble in potash. This
substance is the base of the pigment known in com-
merce as chrome yellow,
864. (C) Iodide of potassium {KI) also gives a beau-
tiful yellow precipitate of iodide of lead (Pbl), which is
i-ather lighter in tint than the chromate. If the iodide
thus formed be boiled with water, it dissolves, and again
separates on cooling, in the form of brilliant crystahine
scales, which are extremely beautiful.
S65. If a solution of nitrate of lead be precipitated
with hydrochloric acid, and the filtered solution treated
with hydrosulphuric acid gas (HS), instead of the black
sulphide usually formed by that reagent in solutions of
lead (357) there is produced a red precipitate, which is
a chloroBulphide j;3PbS,2PbCl). If the gas be passed
through the solution for a length of time, however, the
red compound gi-adually disappeai's, and the black sul-
phide (PbS) is tbrmed.
366. (C) All the precipitates formed in the foregoing
experiments, when dried, and heated on charcoal in the
inner flame of the blowpipe, are decomposed, and give
beads of metallic lead (356).
SECTION VI.
Oxide of Copper (C,nO).
A sohitiou of sulphate of copper {CuO,SO^+^Aq) may
be used.
36T. (C) Heated on charcoal in the deoxidizing flame
Ho:toa=vGoO(^lc
of the blowpipe, especially if inixed with carbonate of
Boda, the aalta of copper are reduced, and a malieable
bead of the metal is obtained ; the peculiar color of
which may be seen on scraping off the thin coating of
oside (CuO), with which it is surrounded. In the
oxidizing flame with borax or microcoamic salt, oxide
of copper forms beads, which are green while hot,
becoming blue on cooling.
368. Hydrosulphurie acid (HS) and hydrosulfhate of
ammonia {NH^SjHS) throw down a black precipitate of
sulphide of copper (CuS) from solutions of copper salts,
whether neutral, acid, or alkaline.
369. (C) Ammonia (iV-ff,), when added in small quan-
tity, throws down a pale blue precipitate, consisting of a
basis salt of copper, which immediately redissolves when
the ammonia is added in excess ; the solution thus
formed has a beautiful deep blue color, owing to the
formation of the ammonio-sulphate of copper {SJifUg,
HO,CuO,S03).
370. (C) Potaak {KO) produces in cold eohitions of
copper, a pale blue precipitate of hydrated oxide (OuO,
HO). If the mixture be boiled, or if the potash be
added to a hot solution, the precipitate becomes black,
owing to the decomposition of the hydrated oxide at a
temperature of 212°, and formation of the anhydrous
black oxide (CuO). The potash must for this purpose
be added slightly in excess, as otherwise the precipitate
would consist of basic salt, which would not become
black when boiled.
371. (C) Ferrooyanide of Potassium (K^fFeOy^+SAq)
give8,'eveu in very dilute solutions, a mahogany-colored
precipitate of ferrocyanide of copper (Cus,FeCy3), which
19 insoluble in dilute acids.
372. (C) A piece of clean iron, when placed in a solu-
tion contaming copper, causes a precipitation of metal-
lic copper on its surface (324).
O!i0.S0,+^e=Ga+Fe0,S0,.
This is an extremely delicate test, and by this means
=vGoo(^lc
132 METALS BELONGINO TO CLASS IV.
the whole of the copper may be removed from a liquid,
especially if a slight excesss of acid is present.
SECTION VII.
Oxide of Silver (AgO)-
A solution of nitrate of silver [AgO^NO,^ may be used.
373. (G) Most of the salts of silver when exposed to
light, especially when in contact with organic matter,
gradually become more or less pui'ple, and eventually
nearly black, owing to partial decomposition.
374. (0) When heated on charcoal before the blow-
pipe, all liie salts of silver are easily reduced, and a
brilliant white bead of met-allic silver is formed. In the
oxidizing flame, oxide of silver gives with borax an
opaque white bead; with microcosmic salt, the bead is
yellowish by daylight, and red by candlelight.
875. Hydrosulphurie acid (HS) and hydrosulphate of
ammonia [NJI^SjHS) throw down ablack precipitate of
sulphide of silver (AgS), which is insoluble in dilute
acids, but soluble in boiling nitric acid.
376. (C) Ammonia {^ffs) gives a brown precipitate of
oxide of silver (AgO), which is readily soluble in excess
Potash (KO) also produces the same precipitate, which
is insoluble in excess.
377. (C) Hydrochloric aeid {SOt) or a solution of chlo-
ride of sodium {NaOl) produces in solution of silver a
white curdy precipitate of chloride of silver (AgCI),
which is insoluble inwaterandin nitric acid, butreadily
soluble in ammonia, and very sparingly so in an excess
eitlier of hydrochloric acid or chloiide of sodium.
AgO,NO-,-lNaa=KgQ\-^NaO,NOi.
If the ammoniacal solution be neutralized with nitric
acid, the chloride is reprecipitated.
378. (0) Phosphate of soda {^NaO,HO,J>0,-^2iAq)
throws down a pale yellow precipitate of trihasic phos-
phate of silver (SAgOjPO^), which is soluble both in
nitrjc acid and in ammonia.
=vGoo(^lc
SECl'ION VIII-
Pmtoxide of Tin (SnO).
A solution of protoehloride of tin {SnQl) may be used.
379. (CJ Salts of tin, mixed with carbonate of soda
(NaOjCOj), and heated in the inner flame of the blow-
pipe, are reduced to the metallic state, and malleable
globules of metallic tin are formed.
In the oxidizing flame, with borax or microeosmic
salt, oxide of tin forms clear, colorless beads, unless a
large quantity of the oxide is present, when the bead is
sometimes opaque.
380. (0) When the neutral protosalta of tin (as the
protoehloride) are treated with a large quantity of water,
they are decomposed into an acid8alt{5'nC?,^t?h which
is soluble, and a basic salt (Sn01,SnO,2HO), which is
insoluble : the precipitation of the latter causes the
liquid to become milky.
3 St «+3ffO=aiCZ,ffCT+SnCl,SnO,2HO.
381. (C) HydrosulpTiurie acid (HS) gives in solutions
of the protosalts of tin, either neuti'al or with excess of
acid, a dark brown precipitate of protosulphide of tin
(SnS), which is soluble in potash and in hydrosulphate
of ammonia, especially if it contains an excess of sul-
phur (710).
882. (C) Hydrosulphate of ammonia {NH^8,_ES) also
throws down the brown protosulphide, which is soluble
in excess, provided a little free sulphur is present in it,
which is always the ease when the hydrosulphate has a
yellow color (710). If the solution thus formed be neu-
tralized with hydrochloric acid, a yellow precipitate of
the persulphide (SnSj) is produced, which was foraied
by the action of the excess of sulphur in the hydrosul-
phate upon the protosulphide. SnS+S— SuS^.
383. Ammonia {NH.^ gives a bulky white precipitate
of hydrated oxide of tin (SnO,HO), which is insolubie
in excess.
SitGi^NJI,+230=S.nO,'B.O+NH^Cl.
384. Potash {KO) also produces a white precipitate
=vGoo(^lc
134 METALS BEI.ONGING TO CLASS TV.
of liydrated oxide (8iiO,HO), which redlasolvca in an
excess of the alkaline solution.
If a concentrated solution of the oxide in potash be
boiled, the protoxide is converted into a mixture of per-
oxide [SnOfi) and metallic tin ; the firat remains in solu-
tion, and the latter precipitates.
385. Carbonate of potash [KO,GO^ also throws down
the hvdrated oxide, which is insoluble in excess.
386. (C) TerchUride of gold{AuCl^ cSMaGSva. eolitvyoB
of the pi-otosalts of tin, a dark purple precipitate, which
has long been known aa purple of Caasius; its composi-
tion appears to be {;2(SnO,SnO,)+AuO,Sn02-|-6UO).
IFor the success of this experiment, it is necessary that
both solutions be exceedingly dilute.
SECTION IS.
Peroxide of Tin, (8nO,).
A solution of the perchloride {SnCl^ may be used.
387. (C) Salts of the peroxide of tin behave in the
eame manner before the blowpipe as those of the pro-
toxide (879).
888. (C) JTydrosulphurie aeid (Hs) gives a yellow pre-
cipitate of persulphide of tin (SnS,), which is soluble in
solution of potash.
389. (C) Sydrosulphate of ammonia {NH^S,HS) also
throws down the yellow persulphide, which is readily
soluble in excess.
390. Ammonia (Nff^) and potash (KO) throw down
a bulky white precipitate of hydrated peroxide of tin.
(SnOj,HO), which is soluble in an excess of the precipi-
tant, especially when potash is «sed, foi-ming a com-
pound called stannate of potash [KO,SnO^, in which
the peroxide of tin appears to play the part of an acid.
The hydrated peroxide, when thus formed by preci-
pitation with potash, is readily soluble both in potash
and nitric aeid, in which respect it differs from that
formed by the action of nitric acid on metallic tin,
=vGoo(^lc
OXIDE OF BISaiUTII. ISD
thougli both yield the eame results when analyzed
(392).
391. (0) Pour a few drops oi nitric acid upon a small
fcagment of metallic tin in a test-tube, and observe the
intense action which immediately takes place. The
nitric acid {NO^ is decomposed by the affinity of the tin
for aportionof its oxygen; the white hydrated peroxide
of tin (BnO^jHO) is formed ; and nitric oxide C^O^ and
some of the other oxides of nitrogen are given off. A
little ammonia (-Wff^), also, ia at the same time formed,
owing to the decomposition of water by the tin ; the
hydrogen combining with some of the nitrogen derived
from wie nitric acid.
392. Heat the hydrated oxide formed in the last
experiment, first with nitric acid and
afterwards in a solution of potash, * *■ "
and observe that it is quite insoluble
in both, thus differing ii'om that
formed by potash (390).
S93. (0) If a piece of clean, ztne
be placed in a solution of perchlonde
of tin, the tin is separated in the
metallic state, in the form of a beau- ^^ ^^^ ^^ ,„,„.„^ ^.u
tiful feathery crystals ; some of which '''' """ "' ' °" "" ""
are so minute, aa to look like an amoiphous spon^^
mass, but when examined with the microscope, appear
as multitudes of brilliant and beautifully fonned crystal-
line tufts (Fig. 74).
Sa a,-f 2Zn=Sa+2i5i CI.
SECTION X.
Oxide of Bismuth (Bi,Os). .'-i l C's
A solution of the chloride {Bi^Gl^ may be used, 'ffi
394. (0) Mix a concentrated solution of the chloride
with a considerable quantity of waier, which causes a
white precipitate of oxychloride of bismuth (BijCi,,
2BiA)-
=vGoo(^lc
136 INORGANIC ACIDS.
A similar decoraposition takes place when solutions
of many of the soluble salts of bismuth are diluted with
much water. The precipitates thus formed are usually
distinguishable from those produced uuder the same
cireumstanees in solutions of antimony, by being in-
Boluhle in tartaric acid (832). They dissolve easily,
however, in acetic acid.
395. (C) "When the salts of bismuth are mixed with
carbonate of soda, and heated in the reducing flame of
the blowpipe, small globules of the metal are foi-mcd,
which break with crystalline fracture when struck with
a hammer. In the oxidizing flame, with boras: or mi-
crocosmic salt, oxide of bismuth forms a yellowish bead,
which becomes nearly colorless on cooling.
396. Sydrosulphuric acid (hs), and liydrosulphate of
ammonia {NH^SjSS) throw down from solutions of
bismuth, which do not contain a large excess of free
acid, a black precipitate of aulphide of bismuth (Bi^S^),
which is insoluble in dilute acid and pot^h, but soluble
in hot nitric acid.
397. Ammonia [NR^ and fotaih {KO) give a white
precipitate of hydrated oxide {BijOs,3HO), which is in-
soluble in an excess of the precipitant.
398. Carbonate of potash {KO, 00^ gives a bulky white
precipitate of subcarbonate of bismuth (BijO^jOOj),
which is insoluble in excess.
399. (C) "When oxide of bismuth is heated, it turns
yellow, and becomes colorless again on cooling.
CHAPTER VI.
ACTION OP REAtiESTS WITH THE INORGAKIO ACIDS.
400. The inorganic acids, which are enumerated in
paragraph (179), may be conveniently divided into
three classes, according to their behavior with chloride
of barium and nitrate of silver, thus: —
Olasa I. — Acids which are precipitated by a solution
of chloride of barium.
=vGoo(^lc
SULPHURIC ACID. 137
Sulpliurie {^0,80^). \ Cai-bonie (CO,).
Phosphoric (PO,). ' SiHcic (SiOa).
Boracic (BO3). ]
Class II. — Aeids which are unaftected by chloride of
harium, but which are precipitated by a solution of
nitrate of silver.
Hydi-oehloric {RO), Hydiiodie {HI), and
Hydrosulphuric (Efl).
Class III. — Those which are not precipitated either
by chloride of barium or niti-ate of silver.
Nitric {NO^ and Chloric {ClO^j.
Sulphuric acid {HO,SO,').
401. Mix a few drops of strong sulphiiric acid or oil
of vitriol with about an equal quantity of water in a
test-tube, and observe the heat evolved.
402. (0) Place a email bit of wood or paper in a
testrtube, and pour upon it a few drops of oil of vitriol :
the organic matter is decomposed^ and black carbo-
naceous matter is fonned.
403. (C) Add a few drops of a solution of chloride of
harium {BaCl), or nitrate of baryta {BaO,NO,^ to one of
sulphate of soda (NaO,SO^ : a heavy white precipitate
of sulphate of baryta ffiaOjSOj) is thrown down, which
is insoluble in hydrochloric acid.
Ba Cl-\-NaO,SOi=Bs.Q,%Q,-^Na CI
404. (C) Acetate of lead {PbO,0^ff^O^-\-2,Aq) throws
down in solutions containing sulphuric acid, a dense
white precipitate of sulphate of lead (PbO,80„) which
is insoluble in dilute acids, but sparingly soluble in
strong sulphuric and hydrochloric acids (691). It is
soluble also in potash and acetate of ammonia (Nff,0,
C,H,0,).
I^O,CiHsO,+m(0,SOt^¥bO,fiO,+NaO,CtH,J\.
405. (C) Mix a little dry sulphate of soda (NaO,_S03)
or some other sulphate, with black flux, and heat it on
=vGoo(^lc
138 INORGANIC ACIDS.
platinum wire in the reducing flame of the blowpipe :
the oxygen both of the eoda and acid is removed, and
sulphide of sodium (N'aS) remains.
NaO,S03+2C =NaS+ 200^.
406. (0) Plaeethebead formed in the last experiment
in a test-tube, and moisten it with a little dilute sul-
phuric acid: hydrosulphurie acid (HS)i9 given off, which
may be recognized by its odor: or by putting into the
tube a strip of paper moistened witH a solution of
acetate of lead, which will be blackened, owing to the
formation of sulphide of lead (PbS) (438).
NaS-f-ift>,50a=JVa 0,SO^+UB.
SECTION ir.
Phosp/ioric AciaQrihasw) (3S0,P0^).
A solution of common tribasic phosphate of soda [^Na
0,B:0,PO^+24Aq) may be used.'
407. Chloride of barium (BaOi) throws down a white
precipitate of phosphateofbai7ta(2BaO,HO,POs), which
is soluble in hydrochloric acid,
2BaCl+2N'aO,HO,POi=2Nam-\-2BM,nO,70^.
408. Chloride of calcium {OaOt) gives a white precipi-
tate of phosphate of lime {8CaO,3P05), which readily
dissolves in a slight excess of hydrochloric acid.'
409. (0) Sulphate of magnesia {MgO,iSOg+1Aq) causes
a white precipitate of phosphate of magnesia (2MgO,
HO,POj), if the solution is tolerably strong. If a little
ammonia or carbonate of ammonia, however, be present
in the solution, the double phosphate of ammonia and
magnesia (2MgO,13'HP,POs+12Aq), is formed, which
being much more insoluble than the phosphate of mag-
nesia, ie precipitated in more dilute solutions, and is
consequently a more delicate test. It separates as a
' The moaobasie (HO,PO,) andbibasicphospioricacid C2H0,P0ii),
being rarely met with in analvsia, are omitted.
* See note to (311).
=vGoo(^lc
PHOSPHORIC ACID, 139
granular ciyatalline precipitate, and is readily soluble in
excess of acid. If the double phosphate be heated to
redness, the ammonia and water volatilize, and the
anhydrous phosphate of magnesia (2MgO,P05) is left
behind (206).
410. (C) Nitrate of Silver {AgO,NO^) throws down a
pale yellow preeipitato of tribasic phosphate of silver
(SAffOiPOg), which is soluble both in ammonia and
nitric acid (310).
■^{Ag 0,N0i)+2Na 0,aO,FO^^SAsO,PO^+2{NaO,I{Ot)SO,NO^.
411. (C) Heat a small fragment of common tribasic
pliosphate of soda before the blowpipe ; when cool, dis-
solve it in water, and add to the aoiution a few dTOpa
of nitrate of silver. Instead of the yeUow tribasic phos-
phate of silver {3AgO,POfi) being thrown down as be-
fore, a white granular precipitate of the bibasie phos-
phate {2AgO,PO,) is produced. This is owing to the
tribasic phosphate of soda having been converted into
the bibasie phosphate {2^3,0,70^} by the expulsion of
the equivalent of basic water, when heated.
412. (C) Acetate of lead {PbO,O^E^O,+SAq) gives a
white precipitate of phosphate of lead (3PbO,P05),
which 18 soluble in nitric acid. If this precipitate be
collected on a filter, dried, and heated before the blow-
pipe, it fuses into a semi-transparent bead, which on
cooling becomes very distinctly crystalline. This test
is decidedly characteristic, not only on account of the
crystalline structure of the bead, but from the circum-
stance that the phosphate, unlike the other saliB of lead,
is not easily reduced to the metallic state when heated
in the inner flame.
418. li perchhride of iron (Fe^Ol^ be added to a solu-
tion of a phosphate acidified with a little hydrochloric
acid, and subsequently mixed with solution o{ acetate of
potash QE"0,(7jff303), the phosphoric acid is tin-own down
in combination with peroxide of iron (2!Fe203,3HO,3
POg). If this phosphate of iron be digested with hy-
drosulphate of ammonia, it is decomposed ; sulphide of
iron (FeS) is formed, and the phosphoric acid remains
in solution in combination with ammonia. The phos-
phate of iron may be still more completely decomposed .
yGoot^lc
140 INORGANIC ACIDS.
by first dissolving it in a slight excess of hydrochloric
acid, and noariy neutralizing with ammonia before the
addition of tlie hydrosulphate.
SECTION III.
Soj'acic Acid (BO3).
A solution of borax {]VaO,2£Og-\-10Aq)m8,yha used.
414. (C) A solution of borax turns turmeric paper
brown, thus resembling an alkali or alkaline carbonate.
Eoraeic acid in solution pi-oduces the same effect,
though in a less degree.
415. Chloride of barium (BaOl) throws down a white
precipitate of borate of baryta {BaO,2B03), which is
readily soluble in hydrochloric acid.
Baai+NaO,2SOi=BaO,2'BO,+2raOl.
416. Nitrate of silver {AgO,NO^ gives a white preci-
pitate of borate of silver (AgCBOj), which is soluble
both in ammonia and nitric acid.
417. (C) If strong sulphuric add {RO,SO^ ho added
to a concentrated solution of a borate, the horacic acid
which is displaced, separates in combination with water
in the form of crystalline scales.
Na 0,WO,+HO,SO-^=Na 0, SOj+ 260,+ /TO.
418. (C) If borax or any other borate be moistened
witli a little sulphuric acid, and the mixture treated with
alcohol, tlie horacic acid is dissolved, and communicates
a green color to the flame when it is burnt. This is
probably owing to a little of the boron (B) being de-
oxidized by the burning spirit, and recombining with
oxygen as it comes in contact with the air at the edge
of the flame.
SECTION IV.
Carbonic Acid (CO;).
The physical and some of the chemical properties of
carbonic acid have been already noticed (18, &c.).
419. (G) The carbonates when treated with a/ree acid
Ho:toa=vGoO(^lc
as hydrocliloric, are decomposed, and the carbonic acid,
being gaseous when uneombined, escapes with efferves-
Ga.OfiO^+ HGl=CaCli-JIO+CO,.
It may be distinguished from other gaseous acids by
being inodorous. When a substance suehae marble ia
tested in this way for carbonic acid, it is generally ad-
visable to drench it with water ; if this la not done,
small bubbles of common air, which at first adhere to
the solid substance, gradually escape, and may lead an
inexperienced peraon to suppose that eft'ervescence is
taldng place.
420. (C) When carbonic acid ia passed into lime water
(OaO), it causes a white precipitate of car-
bonate of lime (CaOjCOa), most of which ^'s "s
redissolves if the gas is passed through
for a length of time, owing to the forma-
tion of the bicarbonate of lime (C(s<?,2C03),
which is soluble in water.
This experiment is best made in a teat-
tube a (Fig. 75), 'to which is connected,
by .means of a perforated cork, a bent
tube, c. A small lump of marble is put
into a, and the tube b half filled with lime-
water : dilute hydrochloric acid is then
poured upon the marble, and the bent tube attached,
which conducts the liberated carbonic acid into the lime-
water, which it immediately renders turbid.
421. Chloride of barium (BaOl) and chloride of calcium
{GaOl) throw down a white precipitate of carbonate of
baryta (BaO,CO^ or of lime (CaOjCOa), which readily
dissolves with e^rvescence in dilate hydrochloric acid.
422. (C) Subacetate of had {ZFb 0,0^11,0,) is an ex-
tremely delicate test for carbonic acid, with which it
forms a white precipitate of carbonate of lead (PbO,
CO,).
423. Most of the carbonates, except those of the al-
kalies, are decomposed when strongly heated; in which
case the oxide or the reduced metal is left (122).
=vGoo(^lc
INORGANIC ACID
SECTION V.
Silicic Acid (SiO,).
There are two modifications of silicic acid, one of wliicli
is soluble, and the other insoluhle.
424. (C) Add a little strong Kydrochlorie acid {SOI) to
a concentrated solution, of silicate of potash {KO,SiO^),
and warm the mixture : a bulky precipitate separates,
which is soluble in potash, while a portion remaina
dissolved in the acid solution ; this is the soluble modi-
fication (probably a definite hydrate) of silicic acid.
KO,SiO,+HCh= Ea+HO+ SiOa,
425. (C) Evaporate to dryness the solution with the
precipitate, formed in the last experiment, and observe,
that on again treating tlie reaiclue ivith hydrochloric
acid, the silicic acid remains undissolved ; in this state
it is almost insoluble also in cold alkaline solutions.
Thus we find, that when the soluble modification of
silicic acid is evaporated to dryness, it is converted into
the insoluble modification.
426. (0) Mix a little dry silicic acid, or an insoluble
silicate, in the fine powder with dry carbonate of soda
{K'aO,C02), and fuse it, for about ten minutes, on a pla-
tinum wire before the blowpipe ; treat the bead with
dilute hydrochloric acid, and observe that the insoluble
silicic acid has been changed, by the fusion with the
alkali, into the soluble modification. If the solution
thus obtained be evaporated to dryness, the silicic acid
again becomes insoluble.
427. (C) When pure silicic acid is fused with eai'honate
of soda before the blowpipe, a transparent colorless bead
of silicate of soda is formed, while carbonic acid is
expelled.
NaO,COj-|-Si03=NaO,Si03+CO,.
In this experiment a small quantity only of the soda
should be used, as it forms an opaque bead when added
=vGoo(^lc
HYDRO CIIL
SECTIOS VL
HydrocMorio AcAd {E(Jl').
(^Chlorine, in combination viilh hydrogen or a •metal.')
A solution of chloride of sodium. [NaQl), or the dilute
acid, may be used.
428. Okloride of barium gives no precipitate. If,
however, it be added to strong hydrochloric acid, the
chloride of barium will be precipitated uuehanged, as it
ia insoluble In the strong acid.'
429. (C) Nitrate of silver {AgO,NO^ throws down a
white curdy precipitate of chloride of silver (AgOl),
which is insoluble in nitric acid, hut readily soluble in
Ag 0,NO^+NaOl=AgGl+mi 0,NO.^.
If the ammoniacal solution be neutralized with nitric
acid, the chloride ia again precipitated.
This precipitate, like most of the salts of silver, be-
comes purple on exposure to light.
430. (C) Acetate of lead {PbO,O^RM^+dAq) gives a
white precipitate of chloride of lead (PbCl) in toiei^bly
strong solutions of chlorides ; if the precipitate be boiled
with a little water, it dissolves, ana separates again on
cooling, in the form of needle-shaped crystals.
Pb 0, C^n^ 0,+Nct CT=PbCl+-Wi 0, CJt^ Ob.
431. (C) "When mixed with nitric acid, and warmed,
hydrochloric acid dissolves gold leaf, forming terchloride
of gold {AuCl^).
^Ha+NO,+A.M=Au Ch+iaO,+^EO.
' This circumstonce must be remembered when testing hydrochloric
acid with chloride of barium, with a \'ieiv to asoertaimng whether it
contains traces of sulplmric acid; in lyhich case it is necessary to dilute
the acid before Icsting.
siGooi^le
INORGANIC
SECTION VII.
Hffdriodic Acid (KI).
(ladtne in combination with hi/drogen or a metal.')
A solution of iodide of potassium (_ff7) may bo used,
432. Ohloride of harium gives no precipitato with liy-
driodie aeid.
433. (0) Nitrate of silver {AgOjNO^ gives apale straw-
colored precipitate of iodide of silver (Agl), wMeh grar-
dually becomes purple when exposed to the light. It
is nearly insoluble in nitric aeid, and considerably less
soluble in ammonia than the chloride (429).
434. (C) Perchloride of mercury {HgOl^ gives a bril-
liant red precipitate of periodide of mercury (Hglj),
which dissolves in an excess either of the perchloride or
of the iodide of potassium.
Hg CTj+2X7=Hgl5+ 2KCL
435. (0) Starch (CjaHj^On,) forma with iodine, even in
highly dilute solutions, a dark purple precipitate of
iodide of starch. If the iodine is in a state of combina-
tion, as in iodide of potassium or hydriodie acid, it is
necessary to liberate it before applying the staroh;
which is readily done by adding a drop or two of nitro-
hydroehloric acid (698), or a solution of chlorine; if
nitric acid is employed, a portion of its oxygen com-
bines with the hydrogen or metal witli which the iodine
was in combination, terming water, or a metallic oxide.
If chlorine be used, it forms with tlie hydrogen or
metal, hydrochloric aeid or a metallic chloride ; iodine
being liberated in either case.
KI+Cl=KCl+I.
The starch may be applied either in solution or as a
paste ; or, what is often more convenient, strips of paper
or cotton may he impregnated with the solution, dried,
and kept for use (T50).
=vGoo(^lc
HYDROSULPHURIC ACID. 145
436. (C) If iodide of potassium, or any other metallic
iodide, m the solid state, be heated with a little strong
sulphuric acid {H0,80^, both compounds arc decom-
posed ; sulphurous acid (SO^) and potash {KO) are formed,
and the iodine is set free.
KI+2(^0,SOa)=£-0,SOa-i-SO,+ 2ifO+I.
A portion of the latter sublimes in the form of a
beautiful violet^eolored vapor, which condenses in the
upper part of the tube, and is highly characteristic.
If the quantity of iodine liberated i8 so email that the
color of the vapor is not perceptible, it may readily be
detected by suspending a bit of paper or cotton mois-
tened with a solution of starch, which will instantly be
turned purple (435).
437. Dilute sulphuric acid when added to the solntion
of an iodide, also causes its decomposition, especially if
the mixture be boiled, setting free a little iodine, which
gives a pale yellowish color to the solution, and causes
a purple precipitate with solution of stai'ch.
SECTION vni.
Hydrmiilphurir. Acid (HS).i
{Sulphur, in comhination loilh hydrogen, or a inetul.')
4B8. (C) Most of the metallic sulphides are decom-
posed when treated with hydrochloric acid, in which
case hydvosulphuiic acid (HS) is given off, and may be
recognized by its disagreeable odor, resembling tliat of
rotten eggs.
Add a little dilute hydrochloric or sulphuric acid to a
small fragment of sulphide of iron (PeS) in a test-tube ;
hydrosulphuric acid is immediately evolved ; and if a
strip of paper, moistened with a solution of acetate of
lead, he held over the open end, it will be blackened,
owing to the formation of the black sulphide of lead
(PbS). The gas may also be passed into a solution of
the acetate, in the manner shown in (420), when it will
throw down the black sulphide (357).
' Galled also Sulphuretted Hi/drogcn.
=vGoo(^lc
14G INORGANIC ACIDS.
¥eS+Ha=FsCl+B.S.
439. (C) When heated with mtriGadd{NO^),t'he nie-
talUc eulphkles are decomposed: the metal is oxidized
at the expense of a portion of the nitric add ; orange
fumes of nitrous acid and nitric oxide being given on ;
while the sulphur separates as a whitish powder, which
gradually collects into yellowish lumps, and is even-
tually dissolved, owing to its conversion into sulphuric
acid, also at the expense of the nitric acid.
CuS+2i^(5s=C«0,SOs+NOj+NO(.
440. (C) The soluble sulphides, or hydrosulphates,
are also decomposed by acids, with evolution of hy-
drosulphurie acid. Add a little dilute liydroehloric acid
to a drop or two of hydrosulphate of ammonia [NH^S,
MS) ; hydrosulphuric acid is given o% while muriate of
ammonia {NMJJl) remains iu solution, and a little free
sulphur ia at the same time deposited, which bad before
been dissolved in the hydrosulphate, causing a white
precipitate.
NH^S,HS+HCl^NS,Cl+%'SB.
When hydrosulphate of ammonia is first prepared, it
is colorless, but a portion of the hydrosulphuric acid is
gradually decomposed by the affinity of the atmospheric
oxygen forits hydrogen, with which it combines to form
water, while at the same time the equivalent of sulphur
is set free {HS-\-0=SO-\-S) ; the latter dissolves in the
hydrosulphate, giving it a yellow color. It is this sul-
phur which is precipitated on the addition of an excess
of acid to the hydrosulphate (710).
441. Ghloride of barium gives no precipitate with hy-
drosulphuric acid, or the bydrosulphates.
442. Nitrate of silver {AgO,NO^) gives a black preci-
pitate of sulphide of silver (AgS), which is soluble in
hot niti'ic acid.
443._ (C) Acetate of lead {PiO,GiH^O^-\2,Aq) throws
down in solutions of hydrosulphuric acid or the hydro-
sulphates, a black precipitate of sulphide of lead (PbS),
which is converted into sulphate of lead (PbO,S03) by
boiling with nitric acid, which furnishes oxygen to both
elements.
=vGoo(^lc
NITRIC ACID.
444. (0) Before the blowpipe, the sulphides ai'e
readily deeompoaed ; the sulphur ie driven off and burns
with a blue flame, forming sulphurous acid (so,), which
may be recognized by ite odor, which is well known as
that of bm'nmg sulphur.
SECTION IX.
mtric Acid (MO^NO,).
Nitrate of potaah (KO,!S'0^'), both solid and in solution,
may be used.
445. Chloride of barium {BaOt) gives no precipitate in
solutions of the nitrates. If it be added, however, to
strong nitric acid, a white precipitate will be produced,
consisting merely of the undecomposed chloride ; which,
though soluble in water, is insoluble in the strong
acid.'
446. Nitrate of silver causes no precipitate in solutions
of the nitrates.
447. (C) If a small fragment of nitrate of potash be
placed on ignited charcoal, vivid deflagration takes
place, owing to the rapid combination of the carbon
with oxygen, which it abstracts from the nitre ; carbonic
acid (cOj) is thus formed, which combines with the
potash previously in combination with the nitric acid.
k:o,no5+c^ko,00j+no3.
448. (0) "When a nitrate ie heated with a little strong
sulphuric acid [110,80^, it is decomposed ; and if cop-
per filings are added to the mixture, the copper becomes
oxidized at the expense of the liberated nitric acid;
nitric oxide and nitrous aeld are given off, forming
orange-colored fumes, which are very characteristic.
EO,N^Oi+3Gii+i(SO,SOi)=3fiCit 0,SOj}+^0, SOs+iSO+NO^.
449. (0) Add a' few drops of strong sulphuric add to
a solution of a nitrate in a test-tubo, and when the mix-
' Tliis mnKt Ije borne in mind when testing tlie puritj of nitric acid.
siGooi^le
148 INORGANIC ACIU.
ture is cold (401), drop in a small crystal of protosnl-
phate of iron (FeO,80j+7Aci). "When nitric acid is
present, a brown compound is formed round the crys-
tal, consisting of protoxide of iron (FeO) in combi-
nation with nitric oxide (NO^), while the other three
equivalents of oxygen combine with another portion of
the protoxide, forming sesquioxide of iron {Fe^O^, which
ia dissolved by the sulphuric acid aa seaquisulphate
(Fe,0„SSO,).
ll)iFe0,8O^+4(RO,SO,)+EO,N'Oi=fiiF(!^O^3SOi)+KO,S0i
If the mixture is heated, the brown compound is de-
composed, and the color disappears.
450. (C) If a little hydrochloric aeid be added to a solu-
tion containing nitric acid or a nitrate, the mixture has
the property of dissolving gold leaf, owing probably to
the liberation of free chlorine, which acts on the metal.
The terchloride of gold {AuCl^ thus formed, gives the
solution a yellowish color,
KO,NOi+2H01^Ka-^2EO^NOt+ CI.
451. Strong nitric aeid has the property of turning
many nitrogenous organic compounds yellow ; a fact of
of which most chemists have unintentionally convinced
themselves while experimenting with nitric aeid, by the
troublesome yellow stains it leaves on the fingers ; the
cuticle being converted into a compound called xan-
thoproteic acid. (2HO,Cs,N,H240,2-)
452. (0) If a nitrate Idc mixed with a little sulphuric
acid, and warmed with a drop or two of sulphate of in-
digo, the blue color of the latter disappears, owing to
the conversion of the indigo into colorless oxidized
compounds.
SECTION %.
Chloric Acid (010^).
Chlorate of potash (KOjOlO^), both solid and in solu-
tion, may be used.
45S. We.itlicr chloride of barium nor nitrate of silver
produce any precipitate in solutions of the chlorates.
=vGoo(^lc
cm.oEic ACID. 149
454. (C) Heat a small fragment of the chlorate in a
t«str-tube with tlie flame of a spirit lamp ; it is decom-
posed, and if the heat ia continued long enough, the
whole of the oxygen is given off. Chloride of potas-
sium (KCl) remains behind.
K0,C10s=KCl+GO.
The presence of oxygen may be proved by introduc-
ing an ignited match into the tube.
456. (0) Dissolve the residue of chloride of potas-
sium formed in the last experiment, in water, and test
the solution with nitrate of stiver (429). The formation
of a chloride after the application of heat is the best
proof that the acid is chloric and not nitric.
456. (C) "When placed on ignited charcoal, or when
heated with organic substances, the chlorates deflagrate
even more violently than the nitrates. On this account
very small fragments only of the chlorate should be
used.
45T. (0) Place a small fragment of chlorate of potash
(KOjClOj) in a test-tube, and pour upon it a few drops
of strong sulphuric acid {I£0,SO^ taking especial care
not to warm the mixture, as it is liable to explode with
violence when heated. The chlorate is decomposed,
sulphate of potash {KO,SO^ and perchloi-ate of potash
{K0,C10^) are formed, together with peroxide of chlo-
rine (oioj, which gives the mixture a yellowish color,
and escapes in the foi-m of a greenish gas.
d{KO,OlO^)-l-2{HO,SO,=2{S:0,SOi)+S:0,ClO.,+20\Oi+2HO.
458. It«peat experiments 448, 449, and 452, using
chlorate of potash instead of the nitrate, and compare
the results with those obtained with the latter.
CHAPTER VII.
ORGANIC ACIDS,
459. The organic acids which are enumerated in
paragraph 179, may be divided into three classes, ac-
=vGoo(^lc
1d(3 organic acids.
cording to their behavior with chloride of calcium and
^erchhride of iron ; thus : —
Qlass I. — Organic acids which are, under certain cir-
Gumetanees, precipitated by a solution of chloride of
calcium.
Oxalic {H0,C30.). I Citric (3H0,Ci,I1^0,,).
Tartaric (2H0,CgH^0J. | Malic (2HO,C8HA).
Class II. — Those which are unaffected by chloride of
calcium, but are thrown down by a solution of per-
chloride of iron.
Succinic (H0,0,H,03). | Benzoic (H0,C„H503).
Class III. — Thoao which are not precipitated either
by chloride of calcium or by perchloride of iron.
Acetic (IIO,C^R,,0.^. \ Formic {IIO,G,BO,).
SECTION I.
Oxalic Acid {TiO,Gfi^).
460. Oxalic acid is readily soluble in water and in al-
cohol.
461. "When crystallized oxalic acid _{HO,C203+3Aq)
is heated in a tube, a portion volatilizes unchanged,
while a part is decomposed.
462. (0) All the salts of the organic acids are decom-
posed at a red heat ; and when the base is an alkali, or
alkaline earth, a carbonate of the base is formed. This
decomposition is almost always attended with a deposi-
tion of charcoal, and consequent blackening ; but in the
ease of the oxalates scarcely anyblackening takes place,
the oxalic acid being almost wholly resolved into car-
bonic acid (GO.,) and carbonic oxide (00) ; the latter of
which escapes, while the carbonic acid combines with
the base.
KO,CsOa-=KO,COs-fCO.
463. (0) Heat a little oxalate of lime (CaO,C303) to
low redness for a few momenta on platinum foil, and
ohseive that the decomposition takes place almost with-
out blaekeuiug. Place the fragment in a test-tube, and
moisten it with dilute hydrochloric acid, when the cffcr-
=vGoo(^lc
TAllTARIC ACID. 151
vGscence will show the presence of carlionic aoid (419,
122).
464. (C) OhUride of calcium (CaCT), when added to
solutions containing oxalic acid, either free or in com-
bination witli a base, causes, even in highly dilute solu-
tions, a copious white precipitate of oxalate of lime
(OaOjC^Og+SAq), which is readily soluble in hydro-
chloric acid, and slightly so in an excess of oxalic acid,
BO that the addition of ammoma favors the precipitation
in an acid solution.
Ca Cl+NHiO, Cj 0,=GsO,Gfi,NIh CI.
The presence of ammoniacal salts does not interi'cro
with the formation of this precipitate.
465. (C) A solution of 8wi/jM(e(6'aO,iS'Os)orany other
salt of lime, causes the same precipitate (CaO,C20j+
2Aq), even in very dilute solutions. Lime-water also
does the same.
466. PeroMoride of iron [Fe^OQ gives no precipitate
in solutions of oxalic acid or the oxalates, unless they
are tolerably concentrated,
467. Nitrate of silver (A^O,NO^) throws down a white
precipitate of oxalate of silver (AgOjCjOg), which is so-
luble both in nitric acid and ammonia. If the precipi-
tate be dried, and heated on platinum foil, it is dispersed
with a slight puff, leaving a residue of metallic silver.
468. (C) "When oxalic acid or an alkaline oxalate is
warmed with strong sulphuric acid {HO,SO^, it is de-
composed into carbonic acid (cOj) and carbonic oxide
(CO), while the basic water or the alkali combines with
the sulphuric acid (33).
The two gases escape with effervescence, and if a
taper be ap^ied as they issue from the tube, the car-
bonic oxide burns with a pale blue flame, combining
with an additional equivalent of oxygen from the air,
and becoming carbonic acid {41).
SECTION II.
Tariario Add (2nO,C3H,0,J.
469. Tartaric acid is soluble both in water and in
alcohol.
=vGoo(^lc
152 ORGANIC ACIDS.
470. (C) Heat a amail crystal of the acid in a tube ;
it at first mses, and is aftenvai'ds decomposed, with de-
position of carbon, and consequent blackening. A
pieculiar and characteristic odor is at the same time
emitted.
471. Fold a email iragment of bitarh'ate of potash
(KOjHOjCgH^Om) in platmum foil, and heat it to redness
before the blowpipe or over a spirit lamp. The tartaric
acid is thus decomposed, and the carbonate of potash
(KO,COj) is at the same time foi-med. Place the frag-
ment in a test-tuhe, and add a few drops of dilute hy-
drochloric acid, when it will effervesce, showing the
presence of carbonic acid (419).
472. (0) OMoride of cahium {CaOl) throws down in
neuti'al solutions containing tartaric acid, a white precipi-
tate of tartrate of lime {2C&0,G^fi^^, which is soluble
in a cold solution of potash; if the potash solutions be
heated, however, the tai^trate of lime separates as a bulky
precipitate, but rediasolves as the solution cools.
473. Lime-water (OaO) causes in neutral solutions a
white precipitate of tartrate of lime (2CaO,CgH(Oja),
which is soluble in an excess of acid. The presence of
ammoniacal salts prevents the formation of this preci-
Eitate, though if the mixture be allowed to stand a few
ours, the tartrate of lime gradually ciystallizes out.
474. Sulphate of lime {OaOjSO^) gives no precipitate
at first, even in neutral solutions of tartrates ; hut if
allowed to stand, tartrate of lime gradually ciystallizes.
475. Salts of potash cause the formation of bitai'ti-ate
of potash (KO,HO,CgH^Oij), which separates from the
solution in the form of a granular precipitate, soluble
in an excess of alkali, and most of the inorganic acids.
If the tartaric acid is present as a neutral tartrate, the
bisulphate of potash (KO,ffO,2SO^ should be em-
ployed for testing it. In dilute eolutioiis the separation
of the precipitate is hastened by agitating the liquid
with a glass rod, when lines of minute crystals will be
deposited on the sides of the glass wherever the rod has
rubbed against it (184, 186).
476. Perekloride of iron {Fe^Ol^) gives no precipitate
witli tartaric acid or the tartrates.
=vGoo(^lc
CITRIC ACID. 153
4T7. (C) Acetate of lead {PbO,0,ff^O,+SAq) tlirowa
iiown a white precipitate of tartrate of lead (2PbO,Oa
lI^Ojp), whicli when washed clean, is readily soluble in
ammonia.
478. Tartaric acid and the tartrates, when present in
Bolntions of the pei-salta of iron, prevent the precipita-
tion of the hydrated peroxide (Fe^OgjSHO) when am-
monia or potash are added (280). This is owing to tho
formation of double tartrates of iron and the alkali,
which are soluble in water, and are not decomposed by
an excess of the latter. Tartaric acid also prevents the
precipitation of alumina, protoxide of manganese, and
some other oxidea, under similar circumstances.
SECTION III.
Oifric Acid (3HO,C„HsOJ.
479. Citric acid is soluble in water and in alcohol,
480. (0) When heated in a tube, citric acid at first
molts, and is subsequently decomposed, emitting pun-
gent fumes, wMcli may be distinguished by tlieir smell
from those formed by tartaric acid under similar cir-
cumstances. A carbonaceous residue remains in the
tube.
481. (0) Chloride of calcium (OaCl), when added to
solutions of neutral citrates, gives a white precipitate
of citrate of lime (30aO,Ci^aOis), which is insoluble in
potash, but soluble in muriate of ammonia. If the am-
moniacal solution be boiled, the citrate of lime repreci-
pitates. Free citric acid gives no precipitate with this
test.
482. (C) Lime-water {OaO) fails to produce a precipi-
tate in a cold solntion, but if the mixture be boiled,
citrate of lime is thrown down, being less soluble in hot
water than in cold.
483. Perchloride of iron {Fe^Ol^ gives no precipitate.
484. Acetate qflead {PbO,0,H^O^+ZAq)t\iVOVfa down
a white precipitate of citrate of lead (SPbOjCj^HgOij),
which when washed, is only very slightly soluble m
ammonia, thus differing from tartaric acid (477).
485. Citric acid and the soluble citrates, when present
=vGoo(^lc
in solutions containing peroxide of iron, alumina, and
some other metallic oxides, prevent their precipitation
by ammonia, owing to the formation of soluble double
salts.
486. Citric acid when heated with sti-ong sulphuric
add, is decomposed ; carbonic acid and carbonic oxide
are given off with effervescence, and after some time,
sulphurous acid (SOj) is formed, and the mixture be-
eotnca dark colored.
SECTION IV.
Malic Acid (2H0,C„H,0,).
487. Malic acid dissolves freely both in water and
alcohol.
488. ^C) When malic acid is cautiously heated in a
tube, it 18 decomposed into two new acids ; maleic acid
{2HO,OgH20g), which being volatile, sublimes and con-
denses in the upper part of the tube; and fumarie acid
(HOjCjHOa) which remains at the bottom. If the heat
is allowed to rise higher than 400'^ or 500°, further de-
composition takes place, and the mass is carbonized.
489. Chloride of ealcium (CaOT) gives no precipitate,
since the malate of lime (2CaO,CgH^Og) is soluble in
water ; the addition of alcohol, however, immediately
causes it to precipitate.
490. Lime water (OaO) gives no precipitate with malic
acid or the malates.
491. PercMoride cf iron [Fe^OQ causes no precipitate,
as the malate of iron is soluble in water.
492. (C) Acetate of lead (PhO,CJf30^+ZAq) thi'owa
down a white precipitate ol malate of lead (PbO,HO,
CglljOA If acetate of lead in solution be allowed to
stand for a day or two on the precipitate, it is gradually
converted into beautiful tufts of si&y crystals. If the
precipitate be well washed, and, while suspended in
water, heated over a lamp, it will be found to melt into
a resin-like mass at the tempei-ature of boiling water.
493. Like tartaric and citric acids, malic acid and the
soluble malates prevent the precipitation of peroxide of
iron and some other metallic oxides by the alkalies
(4T8, 485).
=vGoo(^lc
BENZOIC ACID.
494. "Wlien heated with oil of vitriol (SO.SO;), maVw
acid is decompoBed and carbonized, sulphurous acid
(sOj) being at tJie same time given off.
Succimc Acid (H0,C,H,05).
495. Succinic acid is soluble both in water and al-
cohol.
496. (0) When the pure acid is heated in a tube, it
volatilizes entirely, leaving no carbonaceous residue,
and crystallizes in the upper part of the tube. The
common acid met with in commerce is seldom pure,
and usually leaves a slight residue.
497. Chloride of calcium {OaCl) gives no precipitate
with succinic acid or the succinates.
498. (C) Perchloride of iron [Fe^Cl^ throws down a
bullgr light brown precipitate of persuccinate of iron
(l'ea03,2C^HjOs) from perfectly neuti'al solutions con-
tiuning succinic acid. This precipitate is soluble in
acids, and is decomposed by ammonia, which removes
the greater part of die acid.
^m. Acetate of lead{PhO,OiS^O^-^ZAq]gi-vei.&\vh\te
precipitate of succinate of lead (PbO,CjKjO^), which is
soluble in acid solutions, and is decomposed mto a basic
salt by ammonia.
500. (C) When treated with a mixture of chloride of
harium, ammonia, and alcohol, solutions containing suc-
cinic acid give a white precipitate of succinate of baryta
(BaO,C,H,0,).
SECTION VI.
Benzoic Acid (HO,C,,Hp,).
501. Benzoic acid is scarcely soluble in cold water,
but rather more so in hot ; it is readily soluble in al-
cohol.
502. (C) When heated in a tube, it sublimee and
condenses in the form of beautiful needle-shaped crys-
tals : the vapor has a peculiar aromatic odor, and
causes an unpleasant sensation in the throat, inducing
couffhins^.
=vGoo(^lc
1!)6 ORGANIC ACIDS.
503. Chloride of calcium (QaCl) gives no precipitate in
eolations of benzoic acid, tlie benzoate of lime being
soluble in water.
504. Perchhride of iron {Fe^Ol^ gives in neutral solu-
tions, a light yellowish brown precipitate of perbenzoate
of iron (FejO^jSCuHjOa), which is soluble in acidB, and
lite the succinate, is decomposed by ammonia (498),
505. Acetate of lead {PbO,OJI'30^+SAq) throws down
a white precipitate of benzoate of lead (PbOjCiilljOj) in
solutions of benzoate of potash or of soda, but not in a
solution of the free acid, or of benzoate of ammonia.
506. (0) A mixture of chloride of barium, ammonia,
and alcohol, gives no precipitate with benzoic acid and
tho benzoates, thus differing from succinic acid (500).
507. (C) When the solution of an alkaline benzoate,
as benzoate oi a.iiamoma,(Nff^O,Oi^H^Os), is treated with
strong sulvhuric or hydrochloric acid, it is decomposed,
and the liberated benzoic acid, being almost insoluble
in water, is precipitated in the form of a white ciystal-
line precipitate ; while the sulphate or muriate of am-
monia remains in solution.
SECTION VII.
Acetic Acid (HOjG^B^O;).
508. Acetic acid ia soluble in all proportions in water :
it dissolves also in alcohol.
509. (C) When heated, it volatilizes readily, leaving, it
pure, no residue ; the fumes have an exceedingly pun-
gent odor, resembling that of vinegar, which owes its
active properties to the acetic acid which it contains.
510. Chloride of calcium, and the other salts of lime,
give no precipitate vrith acetic acid or the acetates,
Perchhride of iron ako gives no precipitate, but
changes the color of the solution to a deep reddish
brown,
511. (C) Nitrate of silver {Ag 0,N0.^ causes in neutral
solutions, a white precipitate of acetate of silver (AgO,
C^HaOj), which if the mixture is heated, partially dis-
=vGoo(^lc
FORMIC ACID. 157
solves, and recrystallizee on cooling; it is soluNe in
ammonia.
511a. (C) Protoniti'ate of mercui'y {HgO^NO^ gives
on agitation a precipitate of acetate of mercury (HgO,
C4H3O3), whicli separates intlie form of white silky crys-
talline scales.
512. (0) "When an acetate is mixed with dilute sul-
phuric acid, and gently warmed, it is decomposed ; a
sulphate of the hase being formed, while the acetic acid
is set free, and may be recognized by its odor.
513. (C) If a mixture of an acetate with dilide sul-
phuric acid be distilled (536), and the distilled Hquid
boiled with an excess of oxide of lead (PbO), the libe-
rated acetic acid combines with a portion of the .oxide,
forming subacetate of lead {ZPbO,CiRsO^) ; which,
having an alkaline reaction with test paper, may be re-
cognized by its turning the yellow color of turmeric
paper brown.
514. (C) When acetic acid or an acetate is wanned
with strong sulphuric add {S0,80^, acetic ether
(OjHjOjCjHbO,) is formed, which volatilizes, and may be
known by its peculiar and refi'eshing odor.
SECTION Till.
Formic Acid (HO, O^HO,).
515. Formic acid is readily soluble both in water and
alcohol.
516. (0) "When heated, it volatilizes entirely, giving
off fumes of a peneti'ating disagreeable odor.
517. Chloride of calcium gives no precipitate with
formic acid or the formiates.
518. Perchloride of iron also gives no precipitate,
519. Nitrate of silver gives in strong and neutral solu-
tions of the formiates, a white precipitate of formiate
of silver (AgO,02H03) which shortly becomes of a darker
color, owing to decomposition and the liberation of
=vGoo(^lc
158 ORGANIC ACIDS.
metallic silver. If the mixture be boiled, tliie reduction
takes place immediately.
A similar decomposition takes place witli protoiii-
trate of mercury.
520. (C) "When wanned with dilute sulphuric acid, the
formiates are decomposed : the formie acid volatilizes,
and may be known by its odor.
521. (C) If formic acid or a fbrmiate be heated with
strong sulphuric acid, it is resolved into water and car-
bonic oxide (go). G^S0f=2C0+S0._
The carbonic oxide gas escapes with effervescence,
and burns with a pale Wue flame if a light be applied
to the mouth of the tube.
=vGoo(^lc
PART III.
QUALITATIVE ANALYSIS OF SUBSTANCES, THE
COMPOSITION OF WHICH IS UNKNOWN.
CHAPTER I,
PRELIMINARY EXAMINATION, ETC.
522. "When a Butstance is presented for examination,
with a view to ascertaining its chemical compoeition, it
is obvious that it would be extremely tedious if we were
to begin by applying indiscriminately the tests for the
various metals and acidis, until we happened to meet
with one which gave a characteristic reaction ; and al-
though such a method might occasionally succeed in
the examination of substances consisting merely of one
base and aeid, it would certainly be found whoDy in-
efficient under less favorable circumstances, as when
two or more bases and acids are mixed together, which
would mask or neutralize each other's behavior with
the different reagents employed. Heiice the necessity
of a well-devieed plan of proceeding, in which, by means
of a few simple experiments, we are enabled to obtain
some considerable insight into the nature of the sub-
stance under examination.
523, Before beginning what may be called the real
analysts of a substance, it is generally advisable to make
a few preliminary experiments upon it, in order to as-
certain the class of compounds to which it belongs, and
whether tlie usual mode of analysis will be likely to
succeed with it : this may be called the preliminary ex-
amination.
=vGoo(^lc
JGO PIlBLIMINAItY EXAMINATION.
We will first suppose that a solid substance has been
given to the student for examination. If it is a liquid,
he may pass on to paragraph (533).
SECTION I.
Prellminari/ Exantination of Solids'
524. Observe whether the substance is ceystalline
or AMORPHOUS : whether it is HOMoaEUEOOS throughout,
or composed of different ingredients, such as can be dis-
tinguished either with the naked eye, or with the assis-
tance of a lens.
Kote any peculiarity of form or color ; and observe
whether or not it possesses metallic lustre.
525. Take its specific gravity (145). A Itnowledge
of this is frequently of great service, especially in the
case of minerals, when by a reference to a table of
speeifi,c gravities,* we are able at once to guess what it
is, and to strike out of the list of possibilities a large
number of substances which it might more or less re-
semble in external appearance.
526. Place a fragment oe the substanob in a small
turs op hard german glass, closed at one end : heat
it first over a lamp, and afterwards in the flame
OF THE BLOWPIPE. ObscrvO (a) WHETHER IT APPEARS TO
UNDERGO ANY CHANGE: if it does not, we infer that the
substance contains no water or organic matter ; that it
is not readily fusible ; and that no volatile substances
are present.
(6) Does it fuse ? and if so, does it continue fluid as
long as the heat is applied, or does it, after a short time,
solidify while still in a heated state ? If it solidifies
while hot, it had probably undergon e what is called the
watery fusion, or melted in ite water of crystallization,
which is gradually expelled, condensing in the upper
part of the tube. If the substance fuses without any
' I cannot too strongly insist once more on the importance of making
careful and accurate notes of all the expei'iments and observations
which are made ; they are not only often absolutely necessary foe re-
ference in the aubaequent Ht^geB of the analysis, but the practice is also
of the greatest value to the student, in cnlfivnting habits of correct ob-
servation andfacilityof expression; besides at the same time impressing
the facts more strongly on his recollection (6).
* Such a table may be found in Dr. Thomson's Mincralogi/, vol. i
p, TIO.
=vGoo(^lc
PEBLIMIKARY EXAMINATIOH OF SOLIDS. 161
other appai'ent change, it probably contains either an
alkali or an alkaline earth.
(c) Dobs rr wholly volatilize? If itdoea, of course
no fixed matter is present, and we are thus enabled to
lessen the circle of our inquii-y very considerably,
{c^ Perhaps a portion volatilizes, leaving a fixed
RESIDUE : hence we infer that the substance under ex-
amination is probably a mixture of two or more sub-
stances.
(e) When the substance is volatile (either wholly or
in part), observe whether the vapor condenses in the
COOL part of the tube ; and if so, whether the matter
deposited is solid (crystalline or amorphous) or liquid ; if
the latter, is it neutral or otherwise to test paper? Is the
vapor COMBUSTIBLE ? Has it any characteristic smell, as
of ammonia, or of burning sulphur, or of arsenic (301) ?
(/) Does the substance under examination blacken
WHEN heated? If it does, we may infer that some
organic matter is present; and if, by continuing the
heat with excess of air on a piece of platinum foil, the
blackness disappears, we may pronounce with certainly
that such is the case. If the burnt mass, when cold,
effervesces on being moistened with DILUTE hydro-
chloric ACID {HOI), while the substance in its original
state does not, we may infer that an organic acid was
present, which, when heated, is converted into carbonic
acid, forming a carbonate (462, 471). In this case, too,
it is highly probable that the base with which the or-
ganic acid was in combination, is either an alkali
Q:>otash or soda), or an alkaline earth (lime, magnesia,
baryta, or etrontia) ; as otherwise the newly-formed,
carbonate would probably have been decomposed,
leaving either a metallic oxide or reduced metal (423).
[ff) In case of carbonization, observe whether any
CHARACTERISTIC SMELL is given off during the decom-
position (470, 480), and also whether the vapor which
is formed is neutral, acid, or alkaline to test paper: if
alkaline, it is probable either that ammonia was present,
or that nitrogen was contained in the organic matter.^
' When an organic substance containing iiitrogen is heated,
(NITj) in almost invariably fovmed during tlie destractive cl
=vGoo(^lc
162 PKELIMINARY EXAMINATION.
It is not to be eousidered certain that, because a snb-
staiiee does not cbar when heated, no organic matter ia
present, since many organic substances volatilize with-
out decomposition.
527. Heat a fragment of the substance oh char-
coal IN THE INNER FLAME OF THE BLOWPIPE. In this ex-
periment, some of the appearances already obtained by
heating in a tube {526), will probably be repeated, such
as charring, volatilization, &e. Obsei-ve,
(a) Whether the substamce fuses, eitlier easily or
only after prolonged application of the flame. If fusion
takes place speedily, and especially if the fused mass is
absorbed by the charcoal, it is probable that potash or
soda is present : if the foi-mer, the flame may be tinged
with a violet color (187).
(b) If the substance fuses and boils, and after a short
time SOLIDIFIES while still under the influence of the
heat, the fusion was probably owing to the presence of
water of crystallization (526 b).
(c) If the substance ia inpusiblb (either without or
subsequent to the watery fusion), and remains on tho
charcoal in the form of a colorless infusible mass, the
substance is probably an alkaline earth, silica, oxide of
zinc, or alumina. If an alkaline eai-tb, it willprobably
radiate an intense white light while ignited. The white
infusible mass may then be moistened with a solution of
nitrate of cobalt, and again heated ; when if it becomes
blue, alumina ma^ be suspected (245) ; if green, oxide
of zinc (261) ; and if pale pink, magnesia (209). If it is
silica, it will fuse into a clear colorless bead with car-
bonate of soda, efiervescing at the same time (427).
(d) In case a bead of reduced metal, or a colored
INFUSIBLE EE8IDUB, is formed on the charcoal, it should
be mixed with carbonate of soda (NaO,COs), and again
heated as before on charcoal in the deoxidizing flame.
If tin, copper, silver, or gold are present, a bead of the
metal will be fonned without any incrustation on the
charcoal.* If iron, cobalt, or nickel, are present, they
' The white or browniah ash whieli is always formed when charcoal ia
burnt (which consists of the incorahustible matter of the ehareoall,
must not be tniataken for an incrustation derived fi'om the substance
=vGoo(^lc
PRELIMINARY EXAMINATION OP SOLIDS. 163
will he reduced to the metallic state, but instead of
fusing into a bead, will be mixed up witli the car-
bonate of Boda (being infusible except at a higher tem-
perature), giving the bead a gray opaque appearance.
(e) If a WHITE DEPOSIT la FORMED ON THE CHARCOAL
ROUND THE BEAD OP METAL (or indeed without any
metallic bead), it is pi'ol'3,bly owing to the presence of
zine or antimony.' If zinc, the oxide while hot ia yel-
lowish, becoming white on cooling (260).
(/) If a YELLOW OR A BKOWN DEPOSIT IS PORMED, either
lead, bismuth, or cadmium, maybe supposed to be pre-
sent.
528. Warm a iragment oe the substance in a tube
with strong sulphuric acid {eo,so^: —
(a) If BPFERVESOENOE OCCURS,^ it is probably owing to
the escape of some volatile acid, which is displaced by
the sulphuric acid. If the gas thus liberated has no
smell, carbonic acid may be suspected (419). If it smells
of hydros ulphuric acid, the substance was probably a
sulphide (438), in which case sulphurous acid (sOj)
would probably at the same time be formed. If the
smell resembles that of nitric or nitrous acid, the pre-
sence of a nitrate may be inferred, especially if orange-
■ colored fumes are evolved on the addition of clean cop-
per filings (448). If the disengaged gas is greenish yel-
low, with a smell somewhat resembling chlorine, it is
probably owing to the presence of a chlorate (457).
(6) M organic matter is present (which will have been
already ascertained (526/) ), the escape of gas may be
due to the eai'bonic acid or other gas formed by the
action of the sulphuric acid upon it; and consequently
the presence of a volatile acid is not proved by this ex-
periment, when organic matter is present.
(c) If the substance undergoes no apparent change
by the action of sulphuric acid, the absence of all these
compounds may be inferred.
529. The next point to be ascertained in the preli-
minary examination, is as to the solubility of the eub-
' See note in preceding page.
° Care must ba talieii not to mistake tbe bubbles of common air,
which often escape from the surface of a solid substance when it is
treated with a liquid, for trae efferveecence.
siGooi^le
164 PRELIMINARY EXAMINATION,
stance in water and otlier solvents. Place five or ten
grains of tlie pounded substance in a test-tube, and treat
it with a little distilled water (at first cold, and after-
waiMis boiled if the substance does not dissolve), and
observe whether it is wholly or partially soluble, or
whether it ia absolutely insoluble. This is known by
evaporating a drop of the clear liquid (filtered if neces-
sary) on platinum foil, when, if anything is dissolved, it
will be left as a residue ; wliieh, if abundant, indicates
that the substance is copiously soluble ; and if slight,
that it is only sparingly so.'
{a) If NOTHING IS DISSOLVED by the water, we thus
prove the absence of all soluble compounds.
(i) If it WHOLLY DISSOLVES, we provo the absence of
al! insoluble compounds.
(c) If it PARTIALLY DISSOLVES, it is either a sparingly
soluble substance, or a mixture of soluble and insoluble
matters : the addition of more water wiil show which ot
these is the case. If it is a mixture, the insoluble por-
tion may be separated by filtration from the solution,
for further examination (580).
530. If the substance, or any portion op it, is
found to be insoluble, or but very sparingly soluble,
in water, it must be treated with dilute hydrochloric
ACID [HQl), (except IT BE A METAL, See 531,) AND IF NECES-
SARY BOILED. AVhether or not anything dissolves, may
be ascertained by evaporating a drop of the clear liciuid
on platinum foil (529). If effervescence occurs, it is
probably owing to the escape of a gaseous acid, which
may sometimes be identified by the smell or color
(528 a). If the smell of chlorine be given oft) it may be
owing to the presence of a peraxide, as of manganese
(MnO,).
In case the whole, or any portion, of the substance
prove insoluble in hydrochloric acid, it must be separ-
' It is nlwaya neoeaaar^ to test hy experiment, wliether the dislilfed
■water nsed in these experiments, ia iieelf perfeolJy pure, and free from
dissolved matter; if such were not the case, a residue wonld of course
be left, even though the sabatanoe under examinatioo were insoluble
=vGoo(^lc
PKllLTMI^; AS.Y EXAStJJi Al'ION OF J,I QU 1 ]) S. 1G5
rated by filtration, and retained for farther examination
(532).
531. If the suestancb is a metal (known by its
metallic lustre, &e.), it must be treated tvith strong
nitric acid, and if necessary boiled.
(a) If NO APPAREHT ACTION TAKES PLACE, the metal IS
probably gold or platinum : and if it be found that
nothing has dissolved, the absence of all the common,
easily oxidizable metals may be inferred.
{h) If the METAL IS ACTED UPON, AND A WHITE PRECIPI-
TATE re AT THE SAME TIME FORMED, which is found to be
insoluble in water, it is probable that antimony or tin
is present (391) ; and if, besides the formation of the
white precipitate, some of the metal is dissolved (known
by evaporating a drop of the clear hquid on platinum
foil), the presence of some other metal, soluble in nitric
acid, may be relied on.
(c) If the metal dissolves entirely, the absence of
gold, antimony, and tin, may be inferred.
532. The matter (ie amy) which proved insoluble
IN hydrochloric acid (530), IS NOW TREATED, FIRST WITH
STRONG NITRIC ACID ; AND THEN, IE IT RESISTS SOLUTION,
WITH NITEOHYDRO CHLORIC ACID (698), AHD IE NECESSARY
ROILED. If insoluble in this, it is probably one of the
insoluble silicates, sulphates, or chlorides, and will
have to be afterwards examined (578, 623).
Preh'minari/ Examination, of Liquids.
533. "Wlien the substance given for examination is
liquid, a drop or two should be evaporated on platinum
foil, to asceitain whether or not it contains any fixed
matter in solution. If such isthe case, a small quantity
of the liquid ie to be evaporated to diyness in a basin,
and the residue examined according to the directions
given above for solid substances (524, 526 et seq.). To-
wards the end of the evaporation, when the i-esidue is
nearly dry, and a pellicle of solid matter is formed on
the surface, it is very hable to " spui-t," and project small
portions of the substance out of the basin (644) ; this is
=vGoo(^lc
1, Ij l> P 11 E L 1 M i: S A R Y )i X A M I ^' A 'I I N.
best avoided bj moderating the beat, and by constantly
stirring with a glass rod, so as to prevent the formation
of the pellicle.
"While the evapoi-ation is goin^ on, the following ex-
periments may be comraeneed with the solution.
534. Take its specific geavitt (148).
535. Test the solution with litmus and turmerio
PAPER, to ascertain whether it is neutral or otherwise.
(a) If HEUTEAL, the absence of free acids and alkalies,
and of acid salts, may of course be considered certain.
It is probable, also, that the only salts present are those
of the alkalies or alkaline earths, as the solutions of
most other salts have a feebly acid reaction.
(6) If it has an acid reaction (known by its redden-
ing blue litmus paper), it is owing to the presence of
either an uncombmed acid, an acid salt, or a soluble salt
of one of the heavy metals, many of which have afeebly
acid retiction. To ascertain which of these ia present,
pour a little of the solution into a test-tube, and stir it
with a glass rod, the end of which is moistened with a
solution of carbonate of potash (7f0,(?04+ 2^9); if this
cause a precipitate, the acid reaction ia probably owing
to the presence of a metallic salt : while, if the solution
3 clear, a free acid or an acid salt is probably the
(o) If the solution has an alkaline eeaction (known
by its turning turmeric paper brown), it is probably
owing to the presence of a free alkali or alkaline earth,
one of the alkaline carbonates, or an alkaline sulphide.
In this ease we are enabled to exclude at once all oxides
which are insoluble in alkaline solutions : and if alkaline
carbonates are present, none of the alkaline earths can
exist in solution, since they would be tlii-own down as
insoluble cai'bonates.
536. If the solvent liquid is supposed from its taste
OE SMELL, to he other than water, it may be necessary
to insulate it from the solid matter it contains for ex-
amination. This is best done, if the liquid ia volatile,
by distillation in a small retort (61), or if the quantity
of liquid is minute, the distillation may be effected in
two small tubes, as shown in Fig. 76, a being the retort,
=vGoo(^lc
AUTUAL ANALYyiy,
and 6 the receiver ; the latter may, if n
cool by immemon in cold water. The liquid should
be poured down a long tube-funuel (Fig. 77) to avoid
L
soiline the long limb of a. The distilled liquid may
then be examined as to its taste, smell, specific gravity,
boiling pomt, &e
587 when the substance to be examined is liquid,
containing solid matter in suspension, the latter is to be
separated by filtration, and the solid and liquid portions
examined separately, according to the directions given
in paragraph 524 et seq. and 633 et seq,
SECTION III.
Actual Anoli/sis.
Introductory Remarks.
538. Having learnt from the preliminary experiments
just described the general nature of the substance under
examination, together with its degree of solubility, &c.,
we proceed to the actual analysis by means of liquid
tests, with a view to ascertaining the exact constituents
of which it is composed.
We will first, for the sake of simplicity, and leaving
entirely out of sight all the rai'cr substances (179), de-
scribe the processes to be followed in the analysis of
simple salts which are known to contain only one me-
=vGoo(^lc
168 QUALITATIVE ANALYSIS.
talHe oxide or base, combined with one acid; as, for
example, sulphate of potash {KO,SO,") ; or a binary com-
pound of a metal with a nonmetailie body (or haloid
salt), such as chloride of calcium (CaCl) ; and first those
which are readily soluble in water. It is usual to de-
termine the base first, and when that is done, the student
may pass on to (556), and commence testing for the
acid.
539. "Wlien the presence of any metal or acid is in-
dicated by the action of a reagent employed in qualita-
tive analysis, it is always necessary to confirm our sup-
position by applying other teats ; aa it is rarely the caae
that a single teat is sufficiently decided in its results, to
render the presence of a metal absolutely certain. The
student, therefore, when he is led to infer from the result
of an experiment, that a certain substance is present,
should refer to the action of other reagents on the par-
ticular metal or acid in question ; wben be will have »o
difficulty, by applying two or three of the most charac-
teristic testa to some of the original solution, in proving
his supposition to he correct or otherwise.
CHAPTER n.'
QUALITATIVE ANALYSIS OIT A SIMPLE SALT, CONTAI?;i?r& ONE
BASE AND ONE ACID, WHICH IS READILY SOLUBLE IN
WATER (529).
SECTION r.
Examination of tlis Base of the Salt.
540. Having made a tolei-ably strong solution of the
salts, a little of the solution is treated with a drop or two
of DILUTE HYDROCHLOKic ACID (HOI). If this causcs a
WHITE PEBCiPiXATB, it is probably owing to the presence
' The student will find in tbe Appendix a. list of salta, &c., wliioh may
be taken for practice in qnalilative analysis. He may first examine a
few of each kind with the assistance of the book, until he finds himself
tolerably familiar with tlie processes ; after which he may try them with-
out reference to the printed directions.
=vGoo(^lc
QUALITATIVK ANAl.YRI?, ]6fl
of either Lead^ Silver^ or Protoxide of Mercury, the
chlorides of which, being more or less insoluhle, are
Ereeipitated aa soon as foiined. In order to distinguish
etween them, a portion of the liquid with the precipi-
tate, is supersaturated with ammonia {NH^.
(a) If this DISSOLVES the precipitate, the base is pro-
bably Oxide of Silver (377).
{b) If the precipitate becomes dark coloebd, the base
is probably Protoxide of Mercury (338).
(c) If the PRECIPITATE RBMAIKS UNALTERED by the aUl-
monia, the base is probably Oxide of Lead (362).
In either case, a portion of the original solution should
be tried with some of the moat characteristic tests for
the suspected metal (539).
Hydrosulphuric Add Test.
541. If no precipitate is caused by the hydrochloric
acid, the acidified portion of the solution is mixed with
one of HYDEOSDLPHURic ACID {MS), or the gas may be
passed through it (701) until it smells perceptibly. If
THIS CAUSES NO CHANSB, the student may pass on to
(547) ; but if a precipitate is PRODtrcBD, the base ie thus
shown to be one of these in the fourth class (179), since
none of the others are precipitated from an acidified
solution by bydrosulphuric acid.
542. If THE PEECiPiTATB IS BLACK, the base is either
oxide of Lead, oxide of Copper, oxide of Bisnmih,^ or
peroxide of Mercury. To prove which of these it is,
add to separate portions of the original solution in a
test-tube, the following tests, until one of them is found
to indicate the metal present.
(a) Add a little dilute sulphuric acid {R0,S0^. If
this causes a whitk precipitate, the base is probably
Oxide of Lead, the white precipitate being in that ease
sulphate of lead (PbO.SOj) (361). To confirm this,
add some of the other tests for lead (356, 363, 364).
(5) If THE SULPHURIC ACID OIVBS NO PRECIPITATE, add
to another portion a solution of ammonia [NJT^ ; if this
causes at first a light blue precipitate, which on the
' Bismuth is seldom met with in iasoliible compounds since most of
its salla ave insoluble, or only very sparingly solnblc, in Tvafer.
siGooi^le
170 QUALITATIVH ANAT.YSIS.
addition of ammoiiia in excess, redisaolvea, forming a
deep rich blue soLUTiOS, the base is Oxide of Copper
{369). (Confirm 371, 372.)
(c) To another portion of the original solution, add a
few drops of a solution of potash (KO); if this causes a
TBHOW PEiscipiTATE, the base is Peroxide of Mercury
(351). (Confirai 346, 353, 354.)
((?) If none of these tests succeed, a little of the solu-
tion should be evaporatkd nearly to dryness with
HYDROCHLORIC ACID, aud then added to a considerable
quantity of water in a test-tube ; if a white pebcipitate
is produced, the base is probably Oxide of Bismuth
(394). (Confirm 895, 397.)
543. If the precipitate caused by htdroshlphdric
ACID IS brown, the base is probably Protoxide of Tin
(381). (Confirm 379, 382, 386.)
544. If THE PEECIPITATB CAUSED BY HYDROSDLPHUBIO
ACID IS YELLOW, Cither the base is Peroxide of Tin
(388), or one of the oxides of anenic is present (307).^
To determine which of these it is, add to a portion of
the original solution, a few drops of dilute ammonia ;
if this cause a white precipitate, the baae is probably
Peroxide of Tin (390) (confirm 387, 393); while if the
SOLUTION REMAINS CLEAR, the yollow suIphidc is pi'oba-
bly tbat of Arsenic." (Confirm 303, 312.)
545. If THE COLOR OP THE PRECIPITATE THROWN DOWN
BY HYDBOSULpEURic ACID 18 ORANGE, the base is probably
Oxide of Antimony (329). (Confirm 332, 334.)
546. If THE PRECIPITATE WITH HyDROSULPHURIO ACID IS
WHITE, the base is probably Peroxide of Iron, sulphur
being in that case precipitated (278). (Confirm 280,
282.)
' Although botli of the Oiides of araenic (AbOj and AsOg) liave acitl
properties, they are best iueladed here among the bases, oil account of
their behavior with hydroBuipliuric acid.
' When in the esamiaation of a Bait, the precipitate with hyilrosul-
phurlc acid ia found to be owing to the presence of arsenic, we must
etill seek for the base by further exparimants, since both the oxides of
arsenic are acids. When the substance is soluble in water, the base in
combination with the arsenious or arsenic acid will probably be found
to be one of the alkalies, since the araenites and a ■ ^-- -? -" j.i--
othev metallic oxides arc insoluble in wntcv.
=vGoo(^lc
QU ALl'l'A'i'l VK ANALYSIri. 171
Bydro&idfhaU of Ammonia Test.
547. When liydrosulplmrie acid causes no p]'ecipitate,
it may be infeiTed tliat no metal of the fourth class
(179) is present, and that the metal contained in the
salt belones consequently to one of the three other
claesee. Add a little muriate of ammonia {NSJJTf to
a portion of the original solution, and then a few drops
of dilute AMMONIA, unless tlie solution was quite neutral ;
in which case the addition of ammonia is unnecesBary,
its use being to prevent the presence of any excess of
acid, which might interfere with the action of the hy-
drosulphate of ammonia (440).
548. Add now to the neutrai oe slighily ammonia-
CAL SOLUTION, HYDEOSULPHATB OE AMMONIA. If thlS
causes ko precipitate, none of the metals of the thii-d
class can be present, and the student may pass on to
(553). If A PBECiPiTATE APPEARS, howcver, the base is
thus shown to he one of those included in the third
class : viz. Alumina oxide of Chromium, oxide of Zinc,
pi'otoxide of Manganese, Protoxide of Iron, Peroxide of
Iron, oxide of Nickel, or oxide of Oobalt.
549. If THH PRECIPITATE IB BLACK, the base ie either
protoxide or pei'oxide of Iron, oxide of Nickel, or oxide
of Cobalt. To distinguish between them, add to a fresh
portion of the solution a little caustic potash.
(a) If this causes a dull pale green precipitate,
which on exposure to the air becomes rust colored,'
the base is Protoxide of Iron (273). (Confirm 276.)
(6) If it thi'ows down a rust colored precipitate, the
base is pi-obably Peroa^w^e of Iron (281). (Confirm 282.)
{a) If the precipitate caused by potash is pale green,
which does not become brown by exposure to the air,
the base is probably Oxide of Nickel (288). (Confinn
28T, 291, 292.)
' Muriate of ammoQia is here added to prevent the precipitation of
liny magnesia tliat may be present (200) ; which, as it does not belong
to the third class of metals, might cause confusion.
' When it is expected that a change of color will be caused by ex-
posing a precipitate to the air, the best way is to pour a little of the
precipitate witli the solution containing it, oq a piece of filtering-paper ;
when it will eome more oomplelely in contact wltJi the air than when
allowed to remain in the test-tube.
=vGoo(^lc
(d) If the precipitate ia light blub, ehaiiging to dirty
pink when hoiled, tlie base is probably Oxide of Cobalt
(295). (Confirm 296, 299.)
550. If THE PRKOIPITATE CAUSED BY HYDROSHLPHATB
OP AMMOHiA IS FLESH-COLORED, becoming brown by ex-
posure to the air, the base is probabTy Protoxide of
Manganese (263). (Confirm 264, 267.)
551. If THE PRECIPITATE THROWN DOWN BY THE HYDRO-
BULPHATB IS WHITE, the base is either Alumina or Oxide
of Zinc. To diatinguish between them, add to a fresh
portion of the original solution a little dilute ammohia.
(a) If this causes a witiTE precipitate, which is
KBADiLX SOLUBLE in excess of ammonia, the baac is Oxide
of Zinc (255). (Confirm 260, 261.)
(6) If, on the contrary, the white precipitate thrown
down by ammonia is insoluble in excess, the base is
Alumina (241). (Confii-m 245.)
552. If TFIBPRECIPrrATB CAUSED CY the HYDROSULPHATE
IS GREEN, the base ia probably Oxide of Chromium (247).
(Confirm 248, 251, 252.)
Carbonate of Soda Test.
553. In case neither hydrosulphnric acid nor Jiydro-
sulphate of ammonia produce any precipitate, we know
that no metal of the third orfourth class can be present,
and that the base we are in search of must consequently
belong either to the first or second class.
Add a slight excess of carbonate op soda {NaO,CO.^
TO A portion of THE ORIGINAL SOLUTION: if this causes
NO precipitate, the base does not belong to Class II,
and the student may pass on to (555). If^ on the con-
trary, a WHITE PRECIPITATE IS PRODUCED, the baso is one
of tliose included in the second class, viz. Magnesia,
Jjime, Baryta, or Strontia.
554. To determine which of tliese it is, add to a little
of the original solution in a neutral and concentrated
state, a few drops of a solution of sulphate op soda as
long as it causes any precipitate.
{a) If this causes ho precipitate, even after standing
' The sulphate of lime requires for its solution 500 times its weight
of watai' ; so that even a coiipeiitrated solution of this salt coataina tlie
lime ill a highly tUlutcJ stuto,
=vGoo(^lc
OF SIMPHS SOLUBLE SALTS. 173
a few minutes, the base is probably Magnesia (205)
(confinn 206, 209) ; or lAme in tbe state of sulphate of
lime {OaO,SO;) (215).' (Confirm 216, 217, 219.)
(5) If, on the contrary, a precipitath is PitoDtiOED,
the b^e is either Lime, Baryta, or Strontia : to dis-
tinguish between them, filter the mixture, and test the
clear filtered liquid with oxalate op ammonia. If this
causes a whits prbcipitahs, the baae is probably Lime
(216). (Confirm 215, 218.)
(c) If THE OXALATE CAUSES NO IMMEDIATE PRECIPITATE
IN THE FILTERED SOLUTION, add to a little of the original
solution, a solution of sulphate of limb. If this causes
AN immediate PRECIPITATE, the base is probably Baryta
(225). (Confii-m, 227, 228.)
(a) If THE PRBCIPITATB DOES NOT APPEAK AT FIRST, OU
the addition of the sulphate of lime, but gradually
SEPARATES after some little time, the baae is probably
Strontia (28S). (Confii-m 236.)
555. If neither hydrosulphurie acid, hydrosulpbate of
ammonia, nor cai'bonate of soda, produce any precipitate,
the base is one of the fii-at class viz.. Potash, Soda, or
Ammonia. To ascertain which of these it is,
(a) Add to a portion of the dry salt, ov of the concen-
trated solution, in a test-tube, a little caustic potash
(KO), and boil : if the smell op ammonia is perceptible,
and if the vapor produces dense white ftimes when a
rod, moistened with hydrochloric acid, is held near
the mouth of the tube, the base is Ammonia (195).
(Confinn 192, 194.)
(6) If it is not ammonia, add a little richlobide oi'
PLATINUM to the concentrated solution ; if this causes a
yellow crystalline precipitate, either immediately or
after standing a short time, the base is Potash (185).
(Confirm 186, 187.)
(tr) If KO precipitate appears, and if the solution
from the last experiment, on evaporating spontaneously,
deposits yellow needle-shaped crystals, which are
' Altei' Jetei'inining- the base of a aalt wliieh we know to be soluble
in water, it is of course iiiiuecesaaiy, in tbe Eubseqneiit examination, to
look for any acid tbat forms with the base an insoliible salt. [See Table
of Solubilities, in the Appendix.)
=vGoo(^lc
174 QUALITATIVE ANALYSIS
readily soluble in water, tlie base is Soda (188). (Con-
firm 189, 190.)
SECTION II.
Examination foi- ilie Acid}
556. Having ascertained the base of tbe salt under
examination, we next proceed to discover tbe acid with
which it is combined ; and here we will, as before, for
the sake of simplicity, leave out of sight all the rarer
ones, and confine ourselves to those inorganic acids
which are moat commonly met with in analysis, '
Sulphuric (ffO,SO,).
Phosphoric (PO^).
Boracic (BOg).
Carbonic (cOs).
Silicic (SiOa).
Hydrochloric (HCl).
Hydriodie (hi).
Hydrosnlphnric (HS).
Nitric (HO,NOX
Chloric (flO,aOs).
55T. A portion of the original solution, which for
this purpose should be tolerably concentrated, is first
treated with dilute sulphuric acid. If no apparbht
CHANGE takes place, or if merely a precipitate is pro-
duced, the studont may pass on to (558) ; but if efier-
VESCENCB ENSUES, the acid is probably either Carbonic,
or Hydrosulplmric.
(a) If the gas evolved is inodorous, the acid is pro-
bably Qarhonic (419). (Confirm 420, 421.)
{b) If the gEia has a smell resembling that of rotten
BOGB, the acid is Hydrosulphuric ; or Sulphur combined
with a metal (438). (Confirm 439, 443.)
(c) If the dilute sulphuric acid gives a pale yellow
OR BROWS COLOR to the Solution, the acid is probably
Hydriodie, in wbich case iodine is set free, and being
slightiy soluble, colors the liquid (437). (Confirm 434,
435, 436). (See also 659 b.)
558. H no effervescence is produced by the dilute
sulphuric acid, a portion of the original neutral solution
is tested with chloride o? barium [BaCl) ; if this pro-
duces MO PRECIPITATE, tho studeut may pass on to
(559) ; but if a pbbcipitatg appears, the acid is pro-
bably either Sulphuric, Phosphoric, Boracie, or Silicic,''
' AraeaiouB or arsenic acid, if present, wonld also cause a precipitate
with chloride of barium ; but its presence ■will have been already ascer-
tained during the examination for tbe base of the salt (-544).
=vGoo(^lc
OP SIMPLE SOLUDLB HALTS. 175
ehice baryta forms with each of them an insoluble
salt.
Should any base have been found to be present, which
forms an insoluble or sparing^ysoluble chloride, such aa
lead, silver, &c. (see Table IK, in the Appendix), a
precipitate would here be formed by the chlorine of the
ehlonde of barium. lu such cases, a solution of nitrate
of baryta may be substituted for the chloride.
{a) To distinguish between the acids above enume-
rated, add a little strong hydrochloeic acid to the mix-
ture with the precipitate , if the latter does not dissolve,
the acid is probably Sulphurk, because the sulphate of
baryta is insoluble ; while the phosphate, borate, and
recently precipitated silicate of^ baryta, are soluble in
hydrochloric acid (40S). (Confirm 404, 405.)
If, on the contraiT, the precipitate dissolves in the
hydrochloric acid, the acid is either FhoBphoric, Boracic,
or Silicic.
(S) EVAP0K4TB A LITTLE OP THE ORIOISAL SOLUTION TO
DETNESS WITH HYDROCHLORIC ACID ; ti'eat the residue
again with more of the acid; wash the inaoluble matter
(if any) with water, and examine it before the blowpipe
with carbonate of soda ; if a tbanspaeeht colorless
BEAD is obtained in this way, the acid is probably Silicie
(427). (Confirm 424.)
{e) If it is not silicic, add a little nitrate op silver
to a portion of the original solution ; if this gives a
pale yellow precipitate, the acid is probably Plws-
fUric (410). (Confirm 409, 412.)
(«l) If THE PRECIPITATE THUS PRODUCED IS WHITE, aud
soluble in nitric acid and in ammonia, it is probably
BoraciciAVo). (Confirm 417, 418.)
559. If chloride of baiium causes no precipitate, a
portion of the ori^nal solution must be treated with
miteate op silver (AffO,NOi) : if this causes no preci-
pitate, pass on to (560) ; but if A precipitate is PKO-
DUCED, the acid is probably either Hydrochloric or JZ^-
driodio.
{d\ If the precipitate is white and curdt, insoluble
in nitric acid, but I'eadilj'^ soluble in ammonia, the acid
is Hydrochloric (429). (Confirm 431.)
=vGoo(^lc
176 ftOALITATIVE ANALYSIS.
(J) If THE PRECIPITATE HAS A PALE STKAW COLOR, and
is almost insoluble in ammonia, the acid is probably
Bydriodie (433). (Confirm 435, 436.)
560. If neither chloride of barium nor niti-ate of
silver give aay precipitate, the acid is probably Nitric
or Chloric.
(a) Warm a little of the concentrated solution
WITH STHONO SULPHURIC ACID AND OOPPEK MLISQS ; if
ORANGE FUMES are given off, the acid is probably Nitric
(448). (Confirm 449, 460.)
(i) If the acid is not niti'ic, test a small quantity of
THs SOLUTION FOR CHLORIC -^ciD, in the manner described
in paragraphs (454, 455) and confiiin (457).
CHAPTER ni.
ftUALITATIVE ANALYSIS OF A SIMPLE SALT, CONTAININH ONE
BASE AND ONE ACID (OR A SIMPLE METAL), WHICH IS IN-
SOLUBLE OR NEARLY SO IN WATER, BUT SOLUBLE EITHER
IN HYDROCHLORIC, NITRIC, OR NITROIIYDROCIILOMC ACID
(5S0 BT SEQ.)
SECTION I.
Examination for Base.
561. In dissolving a substance in acid for the purpose
of analysis, it is advisable to avoid using a lai'go excess
of the solvent, since it might afterwards interfere with
the action of some of the reagents ; when a large excess
has inadvertently been used, it is consecLuently neces-
sary to get rid of most of it by evaporation, taking care
of course that sufficient acid is left to retain the sub-
stance in solution. Most of the substances which are
insoluble in water and soluble in acids, owe this solu-
bility to their conversion into compounds which are
soluble in water; as when zinc or marble is dissolved in
dilut« hydrochloric acid, the metallic chloride which is
formed \ZnCl, or C'aGl), is soluble in water, and conse-
quently requires no excess of acid to retain it in solu-
tion. In some cases, however, when the acid acts
merely as a solvent towards the substance, without
causing decomposition, it is iiecessaiy to have an excess
=vGoo(^lc
OP SIMPLE SALTS, SOLUBLE IN ACIDS. 177
of a«icl, to retain it in solution. This is the case with
.the phosphates of tlie alkaline earths, and some other
salts, which would not dissolve again if the whole of
the acid used to dissolve them were to be expelled.
562. When nitiic acid has been employed, either
alone or in conjunction with hydrochloric acid, it is ad-
visable to expel it, and convert the nitrates into chloiides
by adding an excess of hydrochloric acid, filtering if
necessary (as when silver, lead, or mercury are present
(540) ), evaporating the solution nearly to dryness, and
adding water or dUute hydrochloric aeid. The reason
why it is advisable to get rid of the nitric acid is, that
it oxidizes and decomposes hydrosulphuric acid, which
has to be applied as a test, and thus prevents that re-
agent playing its proper part in the process.
Hydrosulphuric. Acid TeM.
563. Dilute the acid solution with three or four times
its bulk of water,' and test a portion of it with hvdko-
SULPHURic ACID ; if this causes so pbecipitate, pass on
to (564) ; but if a pkecipitate is produced, refer back
to (540 to 546), as this part of the examination is con-
ducted in the same way as when the substance is soluble
in water.
Hi/drosiiJphate of Ammonia Teat,
564. If hydrosulphuric acid gives no precipitate, the
base cannot belong to the fourth class. A portion of
the solution shouldnext be neutralized with ammonw,
if it contains an excess of acid, or if neutral, a little
muriate op ammonia should be added (547), and subse-
quently treated with hydeosulphste op ammonia.
If this causes no precihtatb, pass on to (570); but
if A PHEciPiTATG IS THROWN DOWN, the base is probably
one of those belonging to Class III; or else the precipi-
tate may consist of the I^koapkate of one of the Alkaline
■JSartliB, which, in that case, would have been dissolved
by the acid, and repreeipitated unchanged when the
acid was neutralized by the ammonia and hydrosiilphate
of ammonia.
1 If a white precipitate is formed on diluting the acid solution, it is
probable ihat either antimony, bisitrafi, or tin is present {382, S80,
tU).
=vGoo(^lc
ITS ti U A L I T A T I V !■; ANALYSIS
565. If THE PKECIPITATB CAUSED BT THE nTDROSUt-
PHATB IS BLACK, the base is probably protoxide or per-
oxide of Iron, oxide of NicTcel, or oxide of Oohalt. To
dietinguisb between them, apply the test mentioned in
(549).
566. If TUB PBECIPITATETintOWN DOWN BY THE HYDRO-
SULPHATE IS FLESH-COLORED, becoming brown by ex-
posure to the air, the base is -^xobMy Protoxide of Man-
ganese (263). (Confirm 264, 267.)
567. If THE PRECIPITATE IS GKBES", the base is pro-
bably Oxide of Chromium (247). (Confinn 248, 251,
252.)
568. If THB PREOiPiTATB IS WHITE, the baso IS either
Alumina or Oxide of Zine ; or else the precipitate con-
sists of the phosphate (or ammonio-phoaphate) of Mag-
nesia, Lime, Baryta, or Strontia (664).'
To a portion of the original solution, add potash in
excess ; if the pkeoipitate at first formed bedissolves,
the base is either Alumina or Oxide of Zinc, which may
be distinguished from each other in the manner de-
scribed in (651).
569. If THE PRECIPITATE THROWN DOWN BY POTASH IS
INSOLUBLE m EXCESS, it consists probably of an Earthy
Phosphate, the base being consequently Magnesia, Lime,
Baryta, or Strontia. In such a case, it is advisable,
before proceeding to ascertain which of these is the
base present, to separate the phosphoric acid from it.
This is done by adding perehloride of iron [Fe^Cl^ to
the acid solution, and subsequently ammonia in slight
excess ; when the whole of the phosphoric acid is preci-
pitated 'as perphosphate of iron (2FeaO3,3H0,3P05), and
any excess of perehloride of iron is at the same time
precipitated by the ammonia as hydrated peroxide;
leaving in solution a chloride of magnesium, calcium,
barium, or stroutium, together with muriate of am-
monia. The solution thus obtained, and filtered from
the precipitate of iron, may now be tested with carbo-
' Some other salts of ths alkaline earths, as the oxalates and borates,
would, if present, be thrown down when the solution is nentralized ;
being, like the phosphates, soluble only in acid solutions. For the
sake of simplicity, howevei', the consideration of such compounds is
here omitted.
=vGoo(^lc
Oi? PtMPl.E SALTS, SOLUBLE IN ACITIi. ITU
nate of soda, and further examined according to the
directions given in (554).
Carhonate of Soda Test.
570. If hydrosulphate of ammonia causes no precipi-
tate, a portion of the original solution is to be tested tor
the alkaUne earths by supersaturating with carbosate
OP SODA (553, &c.).
571. With regard to the Alkalies, it is hardly neces-
sary to allude to them here, as the compounds which
they form with all the aeids in our list (with the excep-
tion of silicic) are soluble in water. In the case of an
insoluble alkaline silicate, it is only necessary to evapo-
rate a little of the acid solution of it to dryness, and
treat the residue with water. The silicic acid will then
be left insoluble (425), and the aqueous solution of the
alkaUne chloride may be tested for Potash and Soda in
the manner described in paragraph (555).
SECTION II,
Examination for the Acids.
572. If the acid is Arseniotis or Arsenic, it will have
been detected in the course of the examination for base
(563). It is unnecessary to look for Chloric acid, since
all its salts are soluble m water, and consequently can-
not be met with here.
573. A small portion of the substance in the solid
stat« is fiiBt treated with hydrocdloric acid ; if this
CAUSES EFFERVBSOBMCE, the acid is probably Carhonie
(419) (confirm 420) ; or if the gas which is given off
has the SMELL op hyduosolphubic acid, the substance
under examination is probably a metallic Sulphide (438).
(Confirm 439, 444.)
574. If the substance is not acted on bytlie hydro-
chloric acid, TSBAT A LITTLE OF IT WITH JSITEIC ACID, and
if necessary, boil it.
{a) If this CAUSES bffbrvescbkoe, orange fumes of
niti'oue acid being given off, and sulphur at the same
time deposited, Qxe substance is probably a metallic
Suljihide (439). (Confim 444.)
=vGoo(^lc
180 QUALITATIVE ANALYSIS
[h) If the substance dissolves in nitriu acid \?ithout
EFFBKVKSCENCE, add NiTKATG OP SILVER to tliG acid Solu-
tion ; a WHITE CUEDY PKBOiPiTATE, Soluble in ammonia,
indicates HydroeJihrio Acid, tlie original substance being
in tbat case a Chloride (429). (Confirm 431.)
575. Treat a little of tbe substance in the solid state
with STRONO SULPHURIC ACID, and apply heat.
(a) If this causes the disengagement of violet vapok
OF IODINE, the substance under examination is an Iodide
(436).
{b) Add a little alcohoi. to the acid mixture, which
for this experiment should not contain more than a few
drops of sulphuric acid, and apply a light to it in asmall
evaporating dish, placing it in a danc corner, so as to
distmguish the color of tne flame more readily. If the
FLAME IS eiiBEH at the edges, the acid is probably
Boradc (418). (Confirm 417.)
{c) Evaporate to dryness a little of the substance after
boiling with sulphuric acid, and digest the residue in
HOT HYDEOCHLOEIC ACID; if this leaVCS a WHITE INSO-
LUBLE POWDBE, which when washed, and heated before
the blowpipe with carbonate of soda, fuses into a color-
less transparent bead, the acid is Silicie (425, 427).
(d) BUute the hydrochloric acid solution formed in
(c) with water, and add a solution of chloride of barium ;
if this causes a white precipitate, which is insoluble
in nitric acid, the acid is probably Sulphuric (403).
(Confirm 405, 406).
576. In testing for Phosphoric Acid, one of the two
following methods may be adopted, according as the
base of the salt has been found to belong to the second,
third, or fourth class (179).
{a) If the base is one of those in Class IV, the diluted
acid solution of the substance, containing only a slight
excess of acid, is saturated with hydeosdlphuric acid
(701); this precipitates the metal, and sets free the
phosphoric acid (if present), which remains dissolved
in the solution.
The liquid should now be filtered from the precipi-
=vGoo(^lc
Oli" SIMPLE SALTS, SOLUBLE IN ACIDS. 181
tated sulphide, concentrated by evaporation, supersatn-
ratcd with ammonia, and tested witli sulphate os mag-
NBSiA ; if a white crystalline precipitate is gradually pro-
duced, which is insoluble in mui-iate of ammonia, the
acid is probably Thosphorie (409), (Confirm 410, 412^
(6) If the base has been found to belong to Class II,
in, PBKCiiLORiDE OP IRON {Fe^OQ IS added to a por-
tion of the solution of the snbstance in hydrochloric
acid, and subsequently ammonia in slight excess ; the
phosphoric acid, if present, is precipitated in combina-
tion with the iron as perphosphate of iron, together
with a little hydrated peroxide of iron, if the perehloride
has been added in excess. The precipitate thus formed,
containing the whole of the phosphoric acid (if sufficient
perehloride of iron has been added), is now well washed
with distilled water, and digested with the aid of heat
in hydrosulphate of ammonia, by which it is decom-
posed, sulphide of iron and phosphate of ammonia being
formed (413); the latter being soluble,, may be sepa^
rated from the sulphide by filtration, and tested for
Phosphoric Acid with sulphate of magnesia (409).
(Conlrm 410, 412.)
5TT. If the acid is found to be none of those now
referred to, it may be nitric, a few of the subnitrates
being insoluble in water and soluble in acids. To de-
termme this, a little of the substance in a tube is tested
with suLPHUBic acid ahd COPPER PILINGS, when the
appearance of orange eumbs will indicate the presence
of Mtric Acid (448). (Confirm 449, 460.)
CHAPTEK IV.
QUALITATIVE ANALYSIS OP A SIMPLE SALT, CONTAINING ONE
BASE AND ONE ACID, WHICH IS INSOLUBLE OR NEARLY SO
IN WATER, HYDKOCllLOKIC, NITRIC, AND NITROHYDBO-
CHLOEIC ACIDS (532).
578, If tho salt under examination has been found
insoluble in the above solvents, it is probably one of
the following substances, viz., a Silicate of one of the
=vGoo(^lc
182 QIIALTTATIVE ANALYSTS
metals belonging to Class II, III, or IV ; Sulphate of
Lime {CaO,SO,) ; Sulphate of Baryta ffiaO.SO,) ; Sul-
phate of Strontia {&fO,BOs) ; Sulphate of Lead (PbO.SOa);
Chloride of Lead (PbOl), or Chloride of Silver (AgCl).
Some of these Gompounds are not altogether insoluble
either in water or acids, as the sulphate of lime and
chloride of lead ; but since they are only very sparingly
so, it is possible they may be placed under this head by
the exiperimenter.
579. A small fragment of the substance is moistened
with HYDROSULPHATE OF AMMOHIA : if it BEMAIHS WHITK,
pass on to (580) : but if it blackens, it is probably either
Sulphate of Lead, Chloride of Lead, or Chloride of Silver.
A httle of the eubstance in fine powder should in this
case be digested for a few hours in htdrosulphate op
AMMONLA, which Will gradually decompose it, the metal
combining with the sulphur to form an insoluble sul-
phide, while the acid uuitea with the ammonia of tho
hydrosulphate, to form a soluble salt of ammonia.
Thus, in tho case of sulphate of lead, 2(PbO,S03)+
NHASS^2P])B-\-Nff,0,S03-\-E0,S0,.
(a) After filtration, the precipitated sulphide is die-
solved in KiTRic ACID, and the solution thus obtained
may be tested for Lead with sulphuric acid (361), and
for Silver with hydrochloric acid (377).
(6) The solution filtered from the sulphide is next
examined for Sulphuric Acid with chloride of barium
(403), and for Hydrochloric Add {Chlorine) with nitrate
OF SILVER (429), confirmatory experiments being made
in each ease.
580. Kthe substance remaibs white when moistened
WITH hydrosulphate OP AMMONIA, it is prohably either
a Silicate, or the Sulphate of one of the alkaline earths,
Lime, Baryta, or Strontia. A portion of the substance
(about twenty to thirty grains) is reduced to fine powder,
and intimately mixed with four or five times its weight
of dry carbonate of soda. The mixture is placed in a
platinum (or porcelain) ci-ucible,' and heated to redness,
' Great care is neceasnry in nsinj!; a platinum crocible, tliat nothing
is haated in it which is likely to eocrode it. Compounds of tlie easily
reduced and fusible metala, as tin, antimony, lead, bismnth, &e., sub-
atanoes containing sulphuv, as metallic aulpludes, caustic alkalies, n itro-
bjdra chloric atad, besides many oilier HubstanceE, are all more or leas
siGooi^le
either in a furuace or over a lamp, for about an hour
(648). The fused maea, when cool, is digested in dilute
hydrochloric acid until it is for the most part dissolved,
and a little of the solution is tested for SulfTiurio Acid
with CHLORIDE OE BARIUM (403).
ia) If THIS INDICATES THE PRESENCE OF SULPHURIC
ACID, the substance is probably the Sulphate of Lime,
Baryta, or iStronlia, and the acid solution may be neu-
tralized with AMMONIA, and examined for those bases
according to the directions given in (554).
(6) If NO SULPHURIC ACID IS PEESEHT, the substance is
probably a Silicate. In this case the hydroehlovie acid
solution, together with any portion that may have re-
sisted solution, is evaporated to dryness, and the residue
treated witli hydi'oehloric acid, and subsequently with
water ; if a WHITE insoluble powder remains, which
fuses with carbonate of soda before the blowpipe, into a
clear colorless bead, Silicic Acid ia present (425, 427).
The solution obtained in (6), by treating the dry
residue with hydrochloric acid and water-, contains the
base vfith which the silicic acid was combined; and
may be examined according to the directions given in
paragraphs 563 et aeq.
CHAPTER V.
QUALITATIVE ANALYSIS OT A MIXTURE OF TWO Oa MORE
SALTS WHICH MAY CONTAIN ALL THE EASES AND ACIDS
IS THE LIST (179).
Introductory Ilemarlcs.
581, Unless we have reason to know that a substance
intended for analysis contains only one base and one
acid, it is necessary to assume that it may contain any
or all of the more common saline compounds. Such
an analysis is of course considerably more complicated
injucions. When a platinum crucible is heated in a furnace or open
tire, it must be placed in a covered earthen crucible to protect it from
injurj i a little pounded magnesia shoald be interposed between tliem,
to prevent tlieir sticting together, as at a high temperature the surface
of the earthenware is liable to fuse (648).
Ho:toa=vGoO(^lc
184 QUALITATIVE ANALYSIS
than that ,of a single salt ; aud consequently the ne-
cessity of having a well-devised scheme of experiments
is here even greater than in the former case, when only
base and acid had to be determined.
The method of dealing with euch a mixture is, first
to separate the whole of the metals of the fourth class
(if any are present) by passing hydrosulphurie acid gas
throngh a solution of the substance acidified with hydro-
chloric acid, and filtering the solution from the precipi-
tate : the precipitate is then dissolved in acid, and tested
successively for each of the metals of the fourth class.
The filtered solution, containing all the bases but those
of the fourth class, is then neutrahzed, and treated with
hydrosulphate of ammonia, which throws down all the
metals of the third class (if any are present) ; and the
precipitate filtered from the solution is dissolved in acid,
and tested successively for each metal of the third class.
The solution filtered from the sulphides can now only
contain any metals of the first and second class that
may be present, which may readily be distinguished by
a i^i^v simple tests.
582. The student must be careful when making these
experiments, that he adds sufficient of the various re-
agents, to throw down the whole of the metals afl'ected
by them, since any traces of the metals belonging to a
class supposed to have been entirely removed from the
solution, would materially interfere with the indications
afforded by the subsequent tests. For example, in the
analysis of amixture of a ealtoflead anda salt of lime,
if sufficient hydrosulphurie acid were notpasaed through
the solution to separate the whole of the lead, a black
precipitate of sulphide of lead would be formed on the
addition of hydrosulphate of ammonia to the filtered
liquid, indicating the presence of one or more metals of
the third class, none of which are really present. On
the other hand, the addition of a large excess of any of
the reagents is also to be avoided, as oing not only
useless and wasteful, but in many cases mischievous.
Both these errors may he avoided by adding the re-
agents in small successive portions ; and when the ex-
perimenter has reason to think that he has added suffl-
=vGoo(^lc
OP MIXED SOLUBLE HALTS. 185
cient, let him filter a few drops of the mixture, and
apply to the eolution a little more of the reagent : if
this produces no farther precipitate, he may conclude
that enough has been added.
683. 'When a class of metals has been precipitated by
either of the general reagents mentioned in (581), it is
always advisable, before proceeding to apply any of the
subsequent tests to the filtered solution, to ascertain
whether it contains any other fixed bases ; as if it does
not, the examination of it need not be proceeded witli.
This is readily known by evaporating a drop or two of
the solution on platinum foil, and heating it to redness ;
when, if no residue is left, it may safely he concluded
that all the bases (except ammonia, which must be
looked for in a separate portion (602) ) have been al-
ready separated. In the course of an analysis, especially
of a complicated substance, it is often necessaiy to have
several solutions in band at the same time; to avoid
confusion, each of these should be labelled with a hit
of gummed paper, with a letter or mark upon it, re-
feiiing to a corresponding letter in the note hook (7).
584. As one portion of the substance to he analyzed
has to be carried through several operations, it is ad-
visable that the quantity operated on should not he very
small. "When the substance is a sohd, twenty or thirty
grains maybe used; and when in solution, an ounce or
two (according to the degree of concentration) will be
found a convenient quantity.
CHAPTER VI.
QUALITATIVE ANALYSIS OP A MIXTURE OP SALTS WHICH ilAY
COSTAIK ALL THE BASES AND INORGANIC ACIDS IS THE
LIST (179), AND WHICH IS EBADILT SOLUBLE IN WATER
(529).'
SECTION I.
Examination for Bases.
585. The solution is first rendered slightly acid by
=vGoo(^lc
186 QUALITATIVE ANALYSIS
the addition of a few drops of HTDHOcnLORic acid : if
ihia caueea KO pbecipitatb, pass on to (586) ; but if a
WHITE PRECIPITATE IS PRODUCED, it 18 owing to the pre-
sence of Silver, Lead, or Protoxide of Mercury. In this
ease, add hydrochloric acid as long as it causes any-
precipitate; filter the li(iuid, and wash the insoluble
chloride.
Place a small portion of the moist precipitate in a
test-tube, and treat it with ammonia.
(a) If THE PRECIPITATE DISSOLVES COMPLETELY, it COn-
sists wholly of chloride of silver, proving of course the
presence of Silver in the substance under examination
(377). (Confirm 374, 878.)
(&) If THE PRECIPITATE IS BLACKENED, and not wholly
dissolved, by ihei ammonia, it probably contains proto-
chloride oi Mercury (338). (Confirm 336, 844.)
(c) If it appeai-8 to be unaffected ey the ammonia,
it is chloride of Lead (362). (Confirm 861, S6S, 366.)
{d) If it dobs hot wholly dissolve (6 and c), pass
the ammoniacal mixture through a filter, and neutralize
the solution with nitbic acid ; if Silver, in addition to
lead or mercury, is present, it will be reprecipitated aa
chloride (377). (Confirm 374, 378.)
H^dromlphuric Acid Test.
586. The solution, acidified with hydrochloric acid,
and filtered if necessary from the precipitate, is now
treated with hydrosulphuric acid gaa, which must be
passed through it until, after removing the delivering
tube, and blowing the air from the surface of the solu-
tion, the latter smells distinctly of the gas. If no prs-
ciPiTATB IS PRODUCED, eveu on boiling the mixture,
pass on to (593) ; but if on the contrary, A precipitate
lALLS, one or more of the metals of the fourth class are
present : if this is the case, the precipitate must be
separated from the solution by filtration, and washed
salts vliicli are insoluble ia water, as I>arjta and sulphuric acid, oxide
of silver and hjdrocliloric acid, &c. It is consequently unneoeBsarj,
after having determined the bases in a mixture of suits soluble in
water, to look for any acids which form with them sails that are ia-
Buluble. (See Table of Solubilities in flie Appendix.)
siGooi^le
OF MIXED SOLUBLE SALTS. 187
wltli distilled water, until a drop of the wasliinga leaves
no fixed residue when evaporated on platinum foil, the
filtered solution being carefully resei'ved for further
examination (593).'
587. If THE PRECIPITATE PRODUCED BY HYDRO SULPHURIC
ACID IS YELLOW, it may he owing to the presence of
Ar&enie (307), or Peroxide of Tin (388). In this case it
is advisable first to dry a little of the precipitate, and
to test it for arsenic with black flux (303). If arsenic
is thus found to be present, we may at onee conclude
that no bases, with the exception of the alkalies, can be
present, because the compounds of arsenious and ar-
senic acid, with all the other bases, are more or less
insoluble in water, and consequently cannot exist in
an aqueous solution, like that now under consideration.
When therefore arsenic is found, the student may at
once pass on to (601) : and having concentrated the so-
lution, and divided it into three portions, proceed to
examine it for potash, soda, and ammonia.
588. When arsenic is not present, or when the pre-
cipitate CAUSED BY HYDROSOLPHURIC ACID IS ANY OTHER
COLOR THAN YELLOW, it must, after bein^ well washed
(586), be separated from the filter, and digested, with
the aid of a gentle heat, for about a quarter of an hour,
in a small basin, with hydbosulphatb of ammonia. K
the sulphides of Antimony or of Tin are present, they
will dissolve in the hydrosulphate, forming soluble
double sulphides, while the sulphides of the other me-
tals of the fourth class that may be present, will remain
undissolved.^
If the sulphides, or any portion of them remain un-
dissolved by the hydrosulphate, the mixture must
' In quaiitative analysis, the first pottiona only of the wasHngs need
be retained (unless we poeseSB only a amall quantity of the substance),
as the teat would only uaeleaely dilute our BOlution ; but in ^anlUaiive
analysis, it is oeeesaary to retain the whole of them, as their rejection
would occasion a serious deficiency in the weight of the substance un-
[f copper is present, which may be readily ascertained by adding
ionia in excess to the original solution (.^69), sulphide of potassium,
must be subatituted for the hydrosulphate of ammonia, because the lat-
ter would dissolve some of the sulphide of copper.
=vGoo(^lc
188 QUALITATIVE ANALYSIS
be filtered, aiicl tlie insoluble portion well ■washed ; the
solution will then have to be examined for Antimony and
Tin, and the insoluble portion for Letxd, Bismuth, C'of-
per, and Mercury, thna : —
589. Dilute the hydrosulphate of ammonia solution
with about an equal bulk of water, and supersaturate
it with ACETIC ACID, which wiU cause a precipitation of
sulphur (440) and of the sulphides of tin and antimony,
if they are present (830). This precipitate is washed
with water, dried, and a little of it gently ignited on
platinum foil, to prove whether it contains anything
more than sulphur, in which case, a fixed residue is
left ; while, if the whole volatilizes, the examination
of the matter precipitated by the acetic acid need not
be proceeded with, and the student may pass on to
(590), neither tin nor- antimony being present.
If, on the other hand, a residue is left on the pla-
tinum BOIL after ignition, either Tin or Antimony (or
both) are present; in this case the precipitate may be
boiled for about half an hour in a test-tube with strong
HYDEOCHLOitrc ACID, and, after etandiug for a short time
to allow the undissolved sulphur to subside, the clear
solution, which may contain the chloride of antimony
and perchloride of tin,' is poured off.
{a) Dilute a portion of the hydrochloric acid solution
with four or five times its bulk of water : if it becomes
MILKY, Antimony is probably present (332). (Confirm
333, 334.)
(6) Evaporate another portion of the hydrochloric
acid solution to drj'ness, mix the residue with carbonate
of soda, and heat it in the inner flame of the blowpipe;
if MALLEABLE METALLIC SLOBULEs are thus formed. Tin
is probably present (879). (Confirm 384, 386.)
((,') To ascertain whether the tin existed as protoxide
or peroxide, a little of the original solution may be
tested with tebchloridb op gold, which gives a purple
PRECIPITATE with Protomlts of Tin (386).
'If the tin existed as protoxide, and consequentlj' as pTOtosuIpMde
{SnS) in the precipitate thrown down by hjdrosTilphuric acid, it will
have been converted into the persulphide (Snsj) by the aedon of the ex-
ees3 of anlphiir usQally present in the hjdroaalphate of ammonia (382.)
=vGoo(^lc
or MIXED SOLUBLE SALTS. 189
590. The portion of the sulphides which did not dis-
solve in the hydrosulphate of ammonia (588), must now
be examined for Lead, Bismuth, Oopper, and Mercury.
The precipitate is removed from the filter, into a
email evaporating basin, and boiled with stronh Nrraio
ACID for about a quarter of an hour : the solution is then
diluted with water, and if anything remains uudia-
Bolved, filtered.
591. The undissolved matter may contain sulphide
of mercury, sulphur and sulphate of lead; the suljHnirie
acid of which will have been formed by the action of
the nitric acid on the sulphur of the sulphides.
{a) Heat a little of it on platinum foil; if a white
RESIDUE is left after ignition, which blackens when
moistened with hydrosulphate of ammonia, Lead is pro-
bably present (861). (Confiim 366.)
(5) Mix another portion of the dried residue with car-
bonate of soda, and heat it in ahard glass tnbe ; if Mer-
cury is present, metallic globules will condense in the
upper part of the tube (836).
592. The nitric acid solution (590) may contain lead,
copper, and bismuth.
{a) EVAPOHATE THE SOLUTIOS NEAKLY TO DRYSBSS, ASD
DILUTE IT WITH WATER; if a WHITE pRECiPixATEi is pro-
duced, Bumuth is probably present (394). (Confirm,
395, 39T.)
(5) To the solution formed in {a), filtered, if necessary,
from the precipitate, add dilute sdlpburic acid ; if
this causes a whitb precipitate. Lead is probably
present (361). (Confirm 363, 366).
(c) To another portion of the clear solution {a) add
AMMONIA in slight excess ; if this gives a pale blue
precipitate, which readily redissolves in excess of am-
monia, forming a BLUB solutios, Copper is present
(369).
Hi/droml^phate of Ammonia Test.
593. A few drops of the solution filtered from the pre-
cipitate thrown down by hydrosulphuric acid, or which
failed to produce a precipitate with it (686), are now
evaporated on platinum foil, to ascertain whether it
=vGoo(^lc
190 QUALITATIVE A [J A L Y SIB-
contain any otheT fixed base ; and if it is found to leave
NO RisiDUE the examination need not be proceeded
with ; but if A eesidtje is left, a small portion of the
solution is neutralized with ammonia in a teat-tube, and
treated with hydrosulphate of ammonia. If this gives
HO PBEOIHTATE, the Bolution does not coiitaiii any of the
metals in the third class, and the student may pass on
to (596); but if a precipitate appears, the whole of
the liquid is similarly treated, first with ammonia and
then with the htdrosulphatb ; a little mdeiatb of am-
monia being ako added, unless the solution contained
a decided excess of hydroehlorie acid, in which case,
the muriate would be foi'med on neutralizing the acid
with ammonia.*
When the hydrosulphate has been added as long as
it causes any precipitate, the liquid is filtered, and the
precipitate well washed^ until a drop of the washings,
when evaporated on platinum foil and ignited, leaves
no fixed residue," the clear solution being retained for
further examination (596).
594. The precipitate is dissolved in NiTHOHXDEOCiiLo-
Eic ACID, heat being applied if necessary; and if any
sulphur remains undissolved, the mixture is filtered.
The solution thug obtained may contain Peroxide of
Iron, Alumina, and the oxides of Ohrommm, Manganese,
Zinc, Niehel, and Cobalt.
(a) Ammonia ie now added in excess, which precipi-
tates the peroxide of iron, alumina, and oxide of chro-
mium, while the four remaining oxides, if present, are
redissolved. If ko precipitate rbmaihs, pass on to
(595).
{b) If A PRECIPITATE IS FORMED BYTHB AMMONIA, the
mixture is filtered ; and the precipitate, after being
washed, ie redissolved in hydrochloric acid.
{c) Potash is added in excess to the hydrochloric
acid solution : if this causes A precipitate which IB
INSOLUBLE in EXCESS, Peroxide of Iron is probably pre-
sent (281). (Confirm 282.)
{d) The potash solution, filtered if necessai-y, from
the precipitate (c), may contain alumina and oxide of
' See note to S4t. ^ See note to 586.
=vGoo(^lc
OF MIXED SOLUBLE SALTS, 191
chromium. If oxide of chromium is present, the solu-
tion will prohablj' have a green color, and on boiling
the potash solution, the hydrated oxide of Chromium
gradually separates as a dark green precipitate, leaving
flie solution colorless (249). (Confirm 251, 252.)
(e) If Alumina is present, it will he precipitated
PBOM THE POTASH SOLUTION on the addition of muriate
OF AMMONIA (242), especially if the excess of alkali be
first nearly neutralized with hydrochloric acid. (Con-
firm 240, 245.)
595. The ammoniacal solution (594 a) is now to bo
examined. A drop or two are first evaporated on pk-
tinum foil, when if no fixed residue remains, proving
the absence of fixed bases, the examination need not
be proceeded with ; but if any residue is lsft, the
ammoniacal solution is treated with hydrosulphate of
AMBfONiA as long as it produces any pivjcipitate. This
precipitate is rediesolved in nitrohydrochlorie ackl, and
the solution supersaturated with potash. If a preci-
pitate is formed, the mixture is filtered, and the pre-
cipitate washed,
(a) The filtered solution may contain oxide of Zinc.
If this is the case, the addition of hydeosulphuric acid
to the potash solution throws down the white sulphide
(256). (Confirm 260, 261.)
(6) The precipitate (if any) thrown down by potash,
which may contain the oxides of manganese, cobalt, and
nickel, is warmed with a solution containing ammonia
and carbonate of ammonia : if aiw of the precipitate
REMAINS UNDISSOLVED, oxide of Manganese is probably
present. (Confirm 267, 268.)
(n) If any fixed residue is left when a drop of the
ammoniacal liquid formed in (6) is evaporated on pla-
tinum foil, it may contain the oxides of cobalt and
nickel. In this case, evaporate the solution to dryness,
and test a little of the residue with borax before the
blowpipe, for OoMlt (299). (Confirm 295, 296.)
{d) Add a little hydrochloric acid to the other portion
of the residue fonned in (c), and expel the greater part
of it by evaporation, leaving only a slight excess of
acid. .Dissolve it in water, and add a solution of
=vGoo(^lc
192 QUALITATIVE ANALYSIS
CYANIDE OP POTASSIUM Until any precipitate that maybe
fonned is entirely redisaolved : if tlie addition of dilute
sulphuric acid to the solution gradually causes a pre-
cipitate, Nickel is probahly present (291), (Confirm
287, 288.)
Oarhonaie of Ammoma Test.
596. The eolution filtered from the precipitate thrown
down by hydrosulphate of ammonia, or which failed
to produce a precipitate with that reagent, is now to
be tested. A few drops are first evaporated on plati-
num foil, and if ho fixed residue remains, it need not
be examined for any other fixed basis, and ammonia
only will have to bo looked for in addition to the bases
already discovered (see 602 for the method of testing
for ammonia).
If, on the contrary, a eesidub is left, the solution is
boiled for some time to expel the hydrosulphuric acid,
a little hydrochloric acid having previously been added
if hydrosulphate of ammonia had been used.
If any sulphur ia precipitated in this process, it must
be separated by filtration.
The solution is now mixed with a little muriate of
ammonia, unless already formed by neutralizing an
excess of ammonia or the hydrosulphate with hydro-
chloric acid ; carbonate op ammonia, mixed witli a
little ammonia (712), is added as long as it causes any
precipitate, and the solution is boiled. If Ho precipi-
tate is thrown down, the student may pass on to (598J,
neither lime, baryta, nor strontia being present ; but if
A precipitate falls, it is owing to the presence of one
or more of those bases. In mis case the mixture is
filtered, and the precipitate (which may contain the
carbonates of the alkaline earths just mentioned) is
well washed, the filtered solution being retained for
subsequent examination (598).
597. The precipitate ia dissolved in a small quantity
of hydrochloric acid ; the solution thus formed ia
neutralized with ammoni^i, and divided into three por-
tions.
=vGoo(^lc
OF MIXBD SOLIiliLK SALTS. 193
(a) Add to the fii-sfc, sulphate of soda as long as it
causes any precipitate, and filter. If oxalate op am-
monia gives witli the filtered solution a white precipi-
tate, Zime is present (216). {Confirm 219.)
(6) To the second portion add a solution of sulphate
OF LIME ; if this causes an immediate white precipi-
tate, Bar}/ta\s probably present (225), (Confirm 228.)
(e) The third portion is evaporated to diyness, and a
little of the residue heated before the blowpipe ; if the
FLAME IS TiNSBD WITH A CAEMiKB COLOR, Strojitia is pro-
bably present (236). (Confirm 232, 233.)
598. The liquid filtered from the precipitate caused
by the carbonate of ammonia, or which failed to give
a precipitate with that reagent (596), is now to be
examined. If it leaves any residue when evaporated
on platinum foil, it may contain Magnesia, Potash, and
Soda.
"When lime, baryta, or strontia have been detected in
the mixture, it is always advisable to test a little of the
solution filtered from the carbonates, with oxalate op
AMMOKiA and SULPHATE OF SODA, in order to see whether
the whole of the three earths had been separated by the
carbonate of ammonia : if either of the tests ahows
traces of them, the solution is to be again boiled with
a fresh addition of ammonia and carbonate of ammonia,
until the whole of tliem is removed.
599. A little of the ammoniacal solution, moderately
concentrated, is novi- tested with phosphate of boda ; if
this causes a white crystalling precipitate. Magnesia
is preseiit (206). (Confirm 208, 209.)
600. If MAGNESIA IS NOT PRESENT, tbc ammouiacal
solution is evaporated to di-yness, and the residue ig-
nited to expel the ammoniacal salts ; the residue is then
dissolved in as small a quantity as possible of water,
and the solution divided into three portions, to be tested
according to the directions given in (601).
When MAGNESIA IS PREBEHT, it IS ncccssary to sepa-
rate it from the solution by some reagent which does
not contain soda, since that alkali has still to be sought
for in the solution. In such a case, the following is
the best method. TJie remaining portion of the am-
17
=vGoo(^lc
104 QUALIIATIVli ANALYSIS
moniacal solution is evaporated to dryness, and the
residue ignited in a small platinum crucible, to expel
the ammoniaeal salts. The itsed matter ia dissolved in
a little water, treated with a saturated solxitioh op
CAUSTIC BARYTA, and allowed to stand some little time,
to cause the whole of the magnesia to precipitate (208).
The mixture is then filtered ; DILUTE sulphuric acid
is added in very slight excess to the clear solution, to
throw down the whole of the baryta ; and the liquid,
after boiling, is filtered. The filtered solution is evapo-
rated to diyness, to expel the excess of sulphuric acid ;
and the residue is gently ignited ; this is redissolved
in the smallest possible quantity of water, and the
solution divided into three portions. If No residue is
LEFT after the ignition, neither of the fixed alkalies ia
present.
601. (a) The first portion is tested with bichloride
OP PLATINUM, for Potash (185),
(6) The second portion is acidified with tartaric acid,
also for Potash (186)_.
(c) The third portion ia tested with antimoniate oe
POTASH, for S'oda (189). (Confirm 188, 190.)
602. As the substance under examination has to be ig-
nited during the analysis, it is of course impossible that
ammonia can be detected vrith the other alkalies in the
process now described. A portion of the original
solution is therefore to be mixed with an excess of
caustic POTASH and warmed ; if Ammonia is present, it
may be detected by the smell, or by holding a rod
moistened with hydrochloric acid near the mouth of
the test-tube (195).
SECTION 11.
Examination /or the Acids.
603. The original solution of the substance ia firat
examined with litmus and turmeric paper; if it has an
acid reaction, a little of it is tested in the manner de-
scribed in (635 6), and if it is found to owe its acid
reaction to the presence of free acid, the solution must
be carefully neuti'alized ivith dilute potash ; but if it
is only a metallic saltwhich caused it, the solution may
=vGoo(^lc
OF MIXED SOLUBLi! SALTS. 195
be considered neutral. If, on the other hand, the
liquid has an alkaline reaction, which maybe be owing
to the presence either of a free alkali or of allailine
carbonates or hydrosulphat«s, it must be rendered per-
fectly neutral by hydrochloric acid, and boiled to
expel carbonic or bydrosulphurie acids, if either are
604. To a small portion of the original solution add
ii¥DROCHi.ORlo ACID in excess : if this causes efferves-
cence, carbonic and bydrosulphurie acids may be pre-
sent. If NO EFFERVESCENCE takes place, pass on to (605).
(a) If the GAS IS inodorous, or when passed into
lime-water causes a white precipitate, Oarbonie acid is
present (419, 420).
(6) If the gas has a disasreeablb smell, and when
passed into a solution of acetate of lead, causes a black
or brown precipitate, Sydrosulplmric Acid (Sulphur) is
probably present (488). (Confirm 439, 444.)
Nitrate of Baryta Test.
605. Add to the original solution of the substance,
neutralized if necessary (603J, nitrate op bari;ta as
long as it causes any precipitate. If no precipitate
is formed, pass on to (607). The mixture is filtered,
and the precipitate washed, the clear solution being
reserved for further examination (607). The precipi-
tate may contain Sulphuric, Arsenic, Arsenitms,^ Phos-
phoric, Boracic, and Silicic Adds, in combination with
baryta.
(a) The precipitate is heated with strong hydrochloric
acid, and the mixture evaporated to dryness. The
residue is again warmed with hydrochloric acid, and
the liquid, after boiling, is diluted with a little water, and
filtered if anything remains undissolved, in which case
sulphuric and silicic acids may be present.
(6) Add an excess of hydrochloric or nitric acid to
a small portion of the original solution, and then a few
drops of nitrate oe baryta ; if this causes a white pre-
cipitate, insoluble when the mixture is heated, Suir
phurie Acid is present (40S). (Confirm 405, 406.)
c acids are present, they will Iiave been already
' 11 foi- bases (GST).
=vGoo(^lc
196 QUALITATIVE ANALYSIS
(c) To another small portion of the original solution
add HYDROciiLomc acid, and evaporate tiie solution to
dryness ; if any of the dry residue is insoluble m hy-
drochloric ACID, iSi^za'c J.ei(^ is probably present (425).
(Confirm 427.)
606. The hydrochloric acid solution (605 a) may con-
tain phosphoric and boraeic (as well as aisenious and
arsenic) acids, the compounds of those acids with baryta
being soluble in hydrochloric acid.
(«) Test a little of the original neutral solution with
MURIATE OP AMMONIA and SULPHATE OF MAGNESIA ;' if a
CRYSTALLINE PRECIPITATE is foimed, either immediately
or after standing a short time, Phosphoric Acid is pro-
bably present (409). (Confirm 410, 412.)
(6) Add a little sulphuric acid to a small portion of
the original solution, or of the substance in the solid
state, and evaporate the mixture to dryness. Treat the
residue witb alcohol, and after allowing it to digest a
short time, set fire to it in a dark place : if the flame of
THE ALCOHOL IS COLORED QRBSN, Borocic Aci'i? IS probably
present (418). (Confirm 416, 417,)
Nitrate of Silver Test.
607. The solution filtered from the precipitate caused
by nitrate of baryta, or in which that reagent failed to
produce a precipitate (605), is now examined. It may
contain MydrocTilorie^ Bydriodio, Nitric, and Chloric
Acida: and in addition to these, in ease the original
solution was dilute, or contained ammoniacal salts,
ti-aces of boraeic, arsenious, and arsenie acids. The
solution is treated with nitrate of silveb ; if any pre-
cipitate IS PRODUCED, the mixture is filtered, and the
clear solution reserved for subsequent examination
(a) Add an excess of ammonia to the precipitate ; if
' irtha snTistanoe hoB been found to contain any base that efiuses a
precipitate with snlphuric acid (see Table of Solubilities in the Ap-
pendix), diloride of magnesium must be used inateod of the sulphate.
^ If hydrochloric acid has been used to ueutraliaethe Bolutiou (603),
it will of course be precipitated here, so that it will be necessary to test
a little of the original solution, aeutrBliKed with nitric amd, li
whether any hydrochloric acid or chlorine ia present in it.
=vGoo(^lc
OF MIXED SALSS, SOLUBLE IK ACIDS. 197
IT DOES NOT WHOLLY DISSOLVE, Mydriodic Acid {Iodine),
is probably present (433). (Confirm 435, 436.)
(6) The ammoniacal solutioa formed in (a) is snper-
eatarated with niteic acid : if a white cuhdy pbecipi-
TATE is thrown down, St/droehlorio Acid [OMorine) is
probably present (429). (Confirm 430, 431.)
(c) The acid solution formed in (b) may contain
traces of arsenious, arsenic, and boi-acie acids. The
first two will, if present, have been already found in the
examination for the bases ; the latter may be detected
in the manner described in (606 5).
608. The solution filtered from the precipitate thrown
down by nitrate of silver, or in which that reagent failed
to produce a precipitate (607), may contain Nitric and
Oldoric Acids ; but as nitric acid has been added to it in
the nitrates of baryta and silver, some of the original
solution must be used in this part of the examination.
(a) To a small portion of the original solution, add
SULPHURIC ACID AHD COPPER FILINGS ; if OSAHSE FUMES
are disengaged, Nitric Acid is probably present (448).
(Confirm 449, 450.)
(&) Moisten a portion of the original substance in the
dry state, with strong sulphuric acid: if a aRSBNiSH
GAS is evolved. Chloric Acid is probably present (457).
(Confirm 454, 455, 456.)
CHAPTER Vn.
Qualitative analysis oe a mixture of two ok more
salts, which may contain all the bases and inor-
GANIC acids in the LIST (179), AND WHICH IS INSOLU-
BLE, OR NEARLY SO, IN WATER, BUT READILY SOLUBLE IN
HYDROCHLORIC, NITRIC, OR N ITS HYDRO CHLORIC ACID
Exaininalion for the Bases.
609. When it has been found necessary to use a large
excess of acid to dissolve the substance, it is advisable,
=vGoo(^lc
198 QUALITATIVE ANALYSIS
before beginning the analysis, to expel the greater part
of it by evaporation (561).
610. When the substance has been dissolved in hy-
drochloric acid or nitrohydrochloric acid, it is unneces-
sary to examine it for silver or protoxide of mercury,
because the corresponding chlorides of those metals ai-e
insoluble in hydi-ochloric acid. "When the solution has
been made in nitric acid, a little hydrochloeio acid is
first added to the solution : if this causes so peboipitate,
pass on to (611) ; but if a white precipitate is pro-
duced, Silver, Protoxide of Mercury, and Lead, may be
present. In this case add hydrochloric acid as long
as it causes any further precipitate, filter, and examine
the precipitate with ammonia, as already described (585),
the solution being retained for further examination
(611).
611. When nitric acid has been used in dissolving
the substance, either alone or in conjunction with hy-
droehloi^c acid, it is advisable to expel it before pro-
ceeding to test the solution with hydro sulphuric acid;
because when nitrie acid is present in a solution, the
hydrosulphuric acid is oxidized by it, and is thus pre-
vented from acting in tlie usual manner on the metallic
oxides present. The solution containing nitric acid
should therefore be mixed with an excess of hydro-
chloric acid, fiitered if necessary, and evaporated nearly
to dryness. The concentrated solution is then diluted
with water, and if any milkiness is produced on dilu-
tion, owing to the presence of antimony, bismuth, or
tin, it may be disregarded, as it will not interfere with
the action of the hydrosulphuric acid.
Ili/drosulphunG Acid Test.
612. HYDROSULPHURIC ACID GAB js uow passed through
the dilute acid solution, until it is saturated; if this
causes no precipitate, even when the mixture is boiled,
pass on to (614) ; but if a precipitate is produced, it is
owing to the presence of one or more metals of the
fourth class. The precipitate is to be separated by iil-
tration, and washed as long as a drop of the washings
leaves any fixed residue when evaporated on platinum
=vGoo(^lc
OF MIXED SALTS, SOLUBLE IN ACIDS. 199
foil ; the clear liquid being retained for subsequent ex-
amination (614).
613. The precipitate, which may contain the sul-
phides of all the metals in the fourth class, after being
well washed, is digested with hydros ulphatb op am-
monia ; and the portions, both soluble and insoluble in
the hydrosulphate, are examined in the manner de-
scribed in (688 to 592).
As, however, in this case, arsenic may coexist with
any of the other bases of the fourth class {such com-
pounds being for the most part soluble in acids), it is
necessaiy to examine the precipitate thrown down by
acetic acid from the solution of the sulphides in hydro-
sulphate of ammonia, for arsenic, as well as for anti-
mony and tin. This may be easily done by applying
the reduction test (303).
Mi/drosidpliate of Am
614. The solution filtered from the precipitate thrown
down by hydro sulphuric acid, or which failed to produce
u. precipitate with it (612), is now ti-eated with AMMONIA
and HTDROsuLPHATE OF AMMONIA, and examined accord-
ing to the directions given in (593 to 595). As, how-
ever, a mixture such as we are now considering, which
is insoluble in water, may contain the Uarth^ Phos-
phates, those compounds, if present, will be thrown down
by the ammonia and hydi'osuiphate (564); and it is
necessary to examine the precipitate for lime, magnesia,
baryta, and strontiftj in addition to the metals belonging
to Class ni. These earthy phosphates, if present, will
be thrown down by potash, together with any iron that
may be present (594, c) : that precipitate may conse-
quently contain peroxide of iron, together with the
Phosphate of lAme, Magnesia, Baryta, and Strontia.
{a) The precipitate (594, e) is dissolved in hydrochloric
acid, and to a small portion of the solution thus formed,
PEBROCYANiDB OF POTASSIUM IS added ; if this causes a
BLUB PRECIPITATE, Peroxide of Iron is present (282).
(5) To the rest of the solution, perchloride of iron
is added, and afterwards an exces,? of ammonia; this
throws down the whole of the iron as bydrated peroxide,
=vGoo(^lc
200 QUALITATIVE ANALYSIS
whieli earriea with it in combination any phosphoric
acid that may be present ; while the solution contains,
in the form of chlorides, the Alkaline Earike which
were previously combined with Phospliorie Acid (569).
(c) The liquid thus obtained is tested, after filtration,
for fixed bases, by evaporating a drop on platinum foil ;
and if A RESiDiTE IS LEFT, the solution is examined for
Zme, Baryta, Strontia, and Magnesia, carbonate and
MuaiATR of AMMONIA being added, and the precipitate
and solution treated in the manner described in (597
to 599).
Garhonafe of Ammonia Test
615. The solution filtered from the precipitate caused
by hydrosulphate of ammonia, or in which that reagent
failed to produce any precipitate, is now examined for
the Alkaline Earths and Alkalies, in the manner already
described in the case of substances which are soluble
in water (596 to 602).
SECTION II.
Exuvnination for the Acids.
616. A little of the substance under esaminatiou is
mixed with strong hydrochloric acid : if efpervescenck
TAKES PLACE, carbonic and hydrosnlphuric acids may be
present.
(«) If the gas which ia evolved causes a white pkeci-
pii'ATB when passed into lime-water, Oarhonic Acid is
present (419, 420).
(J) If the gas causes a black oe brown precipitate,
when passed into a solution of acetate of lead, Hydro-
sulphurio Acid (Sulphur in a Sulphide) is present (438).
(Confirm 444.)
617. The solution of the substance in hydrochloric
acid ia now examined for sulphuric, phosphoric, and
silicic acids.
(a) A poi-tion of the hydrochloric acid solution is
tested with chloride of barium ; if this causes a white
PRECIPITATE, which is insoluble when warmed with an
excess of hydrochloric acid. Sulphuric Acid is present
(403). (Confirm 405, 406.)
=vGoo(^lc
OF MIXED SALTS, SOLUBLE IN ACIDS, 201
(h) A little of the hydrochloric acid solution is evapo-
rated to diyiiess, and the residue treated with hydro-
chloric ACID ; if a ITHITE INSOLUBLE POWDER IS LEFT,
which, when washed, and heated before the blowpipe
with eai'bonate of soda, fuses into a transparent color-
less bead, SUicie Aeid is present (425, 427).
(e) Phosphoric acid may be detected in the following
manner. To a portion of the hydrochloric eolation,
PBRCHLORiDB OF IRON is added, and then ammonia in
slight excess; the precipitate thus produced is well
washed on a filter, digested, with the aid of a gentle
heat, in HYDSOSULPiiATB op ammonia, and filtered. If
the solution thus obtained gradually throws down,
when concentrated, a white crystalline precipitate
with sulphate OF magnesia. Phosphoric Acid is pro-
bably present (409, 413). (Confirm 410, 412.)
618. A portion ofthe substance is treated with strong
NITRIC ACID, and, if necessary, wanned.
{a) If orange fumes abb evolved, and a pale yellow
deposit of sulphur is produced, a metallic Sulphide is
present (439). (Confirm 444.)
{b) Add to the niti'ic aeid solution a few drops of
NITRATE OF SILVER ; if this CAUSES A PRECIPITATE, wash it
on a filter, and digest in ammonia. If a white curdy pre-
cipitate is thrown down when the ammoniacal solution
is neutralized with nitric acid. Hydrochloric Acid (a Me-
talUe Chloride) is present (429). (Confirm 430, 431.) _
619. Test a little of the substance for Boracia Acid in
the manner described in (600, b).
620. If the substance disengages violet-colored
FUMES, when warmed with strong sulphuric acid.
Iodine (a Metallic Iodide) is present (436).
621. Place a fragment of the dry substance on ignited
charcoal : if this occasions deflagration, Nitric Acid is
probably present (447). (Confirm 448, 450.)
622. Ohlorio Add need not be looked for in com-
pounds which ai'e insoluble in water, since aJl the chlo-
rates are readily soluble.
=vGoo(^lc
QUALITATIVE ANALYSIS.
CHAPTER Vlir.
QUALITATIVE ANALYSIS OP A MIXTURE OP TWO OB. MORE
SALTS, WHICH MAY C05TAIK ALL THE BASES AND ISOR-
OANIC ACIDS IN THE LIST (1T9), AND WHICH 18 INSOLU-
BLE, OB NEARLY 80, IN WATER AND ACIDS.
623. The compounds most likely to be found in such
a mixture, are those enumerated in (578). The heet
method of rendering such a substance soluble, is to
fuse it with carbonate op soda (580), eithei- in a pla-
tinum or porcelain crucible. If any metals of the fourth
class are present, which may generally be ascertained
by moistening a small fragment of the substance with
HrDROSULPHATB OP AMMOKiA (579), it is Safer to use a
porcelain crucible.' "When this is done, a little silica
and alumina will generally be dissolved from the cru-
cible by the action of the soda, and will appear in the
course of the analysis.
624. The fused mass is treated with water, filtered,
and the aqueous solution, which contains chiefly the
excess of the carbonate of soda used, and some of the
acids of the insoluble mixture must be examined,
according to the directions given for the analysis of a
mixture soluble in water (585, &c.).
625. The portion of the fused matter which is in-
soluble in water will generally be found to dissolve,
when digested, for a few hours, with the aid of a gentle
heat, in dilute hydrochloric or hitric acid ; after
which the acid solution must be examined, according
to the directions given for the analysis of a mixture
which is insoluble in water, but soluble in acids
(609, &c.).
626. When the insoluble substance has to be ex-
amined toT alkalies, as in the case of many siliceous
minerals, it must be rendered soluble by fusion with
carbonate of baryta or lime. As, however, the analysis
of such substances is attended with difficulty, the de-
tails of the process need not here be considered.*
' See note to 580.
* See Itose, "Analyse Ciimiquc," torn., i, p. Gil ; ii, 382 ; also Ptir-
liell's " Elements of Cliemical Analysis," p. 403.
siGooi^le
PART lY.
QUANTITATIVE ANALYSIS.
Introductori/ Remarks.
627. Ih the processes whicli I have now describecl,
the object of the experimenter has been to ascertain
what substances are present in a given salt or mixture
of salts, which branch of analysis ia called qualitative.
I will now detail a few processes which have for their
object the determination of the quantity of the ingredi-
ents of saline compounds : this branch of analyeia is
called quantitative. It is not my intention to enumerate
the methods which have been devised for the separation
and estimation of all, even of the more common com-
pounds, but merely to give the student a geneml idea
of the subject, by conducting him through a few simple
examples of quantitative- analysis, referring him, if he
wishes for more extended information, to the larger
works of Eose, Fresenius, and Parnell.'
628. I will first briefly describe some of the more im-
portant operations which have to be performed in the
course of a quantitative analysis ; and the student must
bear in mind that the more cai'e he bestows upon them,
the more correct will be his results ; as the loss of a
single drop of liquid, or the presence of a very small
quantity of soluble matter left in a precipitate, owing
to carelessness in washing, will often occasion serious
errors.
' " Traire Pratique d'Analjse Cliiiaiqiie, par H. Rose," of ivhicli an
English tainalation by Dr. Normandy has recently appeared.
" Chemioal Analysis, Qualitative and Quantitative,." by C. K. Fre-
senins, translated by Bnllock.
"Elementa o'f Chemical Annly.^is," by E. A. Parnell.
=vGoo(^lc
OPEEATIOKS IN
CHAPTER I.
OPERATIONS IN ANALYSIS.
629. Most substaiicea may be reduced to sufficiently
fine powder for analysis, by pounding in a, common
Wedgwood mortar ; in some cases, however, it ia firet
iieeessaiy to break the substance into small fragmentSj
in one of iron or gun metal ; or in default of this, the
substance may be losely wrapped in strong brown paper,
and etruek with a hammer. "When the substance is
difficult of solution, as in the case of some siliceous
minerals, it ia sometimes necessary to reduce it to an
impalpable powder, in a small agate mortar ; and on
the fineness of this pulverization the success of an
analysis often depends.
Drywj.
630. Many substances, especially when in the state
of powder, absorb moisture
^'s-''^- from the atmosphere, which,
of course, adds to their
weight. Before weighing
out accurately the quantily
of the substance for analysis,
it is therefore necessary to
deprive it of tliis hygro-
scopic moisture. This is
generally done by heating
It in a small basin on the
water-bath or sand-bath,
care being taken that the
heat does not rise so high
as to cause decomposition.
The hot water box shoWn
in figure 78, is veiy con-
venient for drying sub-
stances at a low tempera-
sides are made hollow, and filled with
=vGoo(^lc
WEIGHING. 20r>
water, so that the temperature inside never rises higher
than 212°. "When a enhstanee thns exposed ceases to
lose weight, on being weighed at short intervais, it may
be considered sufficiently diy. By using saline solu-
tions, which boil at a higher temperature than water,
a steady heat, considerably higher, may be obtained
(647).
Weiyhmg.
631. Either 20, 25, or §3-3 grains, will generally be
found the most convenient quantity to take for quanti-
tative experiments, regard being had to the number of
constituents to be estimated, and the quantity of the
substance at our disposal. The quantity may depend
also on the method we intend to pursue, whether we
propose to estimate all the ingredients from the same
portion, or from two or more separate portions of the
substance. If 20 ^raans are used, the results, multi-
plied by five, will give the percentage ; or if 25 or 33-3,
they must be multiplied hy four or three. For most
purposes, the student will find a balance that is capable
of weighing within one-tenth of a grain, sufficiently
accurate ; and it should be furnished with weights from
one-tenth of a grain to 1000 grains.
A substance should never be weighed while warm,
as it causes an upward current of air in its vicinity,
which tends to buoy it up, and makes it appear to weigh
lighter than it really is. In quantitative analysis, it is,
of course, necessary to avoid the slightest loss in the
weighed portion, as a deficiency in the weight of the
ingredients would he the consequence, and the accuracy
of the analysis seriously interfered with. Most sub-
stances in the state of fine powder, especially after
having been recently ignited, are very prone to absorb
moisture from the air ; to obviate this, which would add
materially to their weight, such substances should be
weighed in a covered crucible, ^ soon as possible after
cooling.
When, as is frequently the case, especially with liquids,
a substance has to be weighed in a flask, dish, or other
vessel, the latter may either be counterpoised with
strips of lead or shot, which are conveniently placed in
=vGoo(^lc
206 SOLUTION,
a pill-box ; or its weight may be previously noted, and
afterwards deducted from the gross weight.
Sohuion.
632. Before the ingredients of a substance can be
determined, either qualitatively, or quantitatively, it ie
necessary to bring the substance into solution. For
this purpose, water ia to be preferred when the sub-
stance dissolves readily in it ; and in the case of those
compounds which are insoluble in water, one of the
acids {generally hydrochloric) is employed, which has
been found, in the coui-se of the preliminary examina-
tion, to be the best adapted for the purpose. (529-532.)
The solution of a substance is almost invariably
' ■ i by heat, so that it ia always advisable to use a
vessel for the pui-pose,
which can be heated over
a lamp without danger of
fracture, as a small Berlin
porcelain dish or glass
flask. {Figa. 79 & 80.)
The latter has the advan-
tage of preventing loss by
ebullition or spurting, as
any pai'ticles of liquid that
may be projected from the
surface during ebullition,
fall against the inner sur-
face, and run back into the fiask, especially if it is
placed in an inchned position over the lamp. Occa-
=vGoo(^lc
PllECIPITATION. 207
sional stirring faeilitatea the solution, and, as a general
rule, the more finely the substance has been pounded,
the more readily it dissolves. "When a substance has
to be digested in acid for a length of time, with the aid
of heat, the evaporation of the acid may be in a great
measure prevented, by placing a small glass fannel in
the mouth of the flask (Fig. 81) ; the acid condenses,
and runs back into the flask.
J^ecipitatio'ii.
633. When a substance is obtained in solution, the
various compounds present are in most eases separated
for the purpose of estimation, hy adding to it some solu-
tion, which causes one or more of the ingredients to
precipitate in the solid state ; as, when we wish to esti-
mate the quantity of sulphuric acid in any solution, we
add to it a solution of chloride of barium, which, if
added in sufficient quantity, causes the whole of the
acid to precipitate in the form of sulphate of baryta
(403), which, being insoluble in water, may be washed
without loss, and when dry is weighed ; the weight of
the sulphuric acid which it contains, may then be cal-
culated from it (652).
Precipitation is usually effected in upright glasses of
the forms shown in T"ig. 82. "When precipitating a
substance in quantitative analysis, it is important that
sufficient of the precipitant is added to throw down the
whole of the substance affected by it, as otherwise a
deficiency in weight would
be occasioned : this is easily
ascertained by adding a
drop of the precipitant to
the solution filtered from
the precipitate, which will
cause a further precipitate
if sufficient had not befoie
been added. When the precipitate is at all soluble, as
the bitartrate of potash, or ammonio-pbosphate of mag-
nesia, it is always advisable to allow the mixture to
stand several hours before filtering, in. order to insure
the separation of the whole of the required salt (184).
Jig. 82,
siGooi^le
208 OPEHATIONS IK ANALYSIS.
"When tlie whole of the precipitate is thrown down, it
is separated from the solution either hy filtration or de-
eantation (634, 643).
FiUro.Hon.
634. The process of filtration is that most commonly
adopted for separating a precipitate from the solution
in, which it was formed. The paper best adapted for
the purpose is a thin white hlotting paper, which should
he free from visihle holes, and should leave, when burnt,
only a minute trace of inorganic matter. Such a paper
may be purchased at any of the respectable dealers ia
chemical apparatus. It ia convenient to keep a stock oi
filters ready cut, of a circular form, and of sizes vaiying
from three to ten inches diameter. These may he made
by having circular pieces of tin plate of the different
sizes, and scoring round them with a pencil upon tlie
paper, when several sheets may he cut through at once
with scissors.
635. The filter, when required for use isfoldedtwice
at right angles (Fig- 83) (fab) o].ci ed o it into a conical
form and placed in a glass t inncl tl e slopii g sides of
which should open at in mgle of il o it 60°, when it
will he found to match the fotmof the folded filter, and
will support it uniformly throughout. When placed in
the funnel, the paper is moistened with water, for the
purpose of causing the fibres to expand, and thus dimin-
ishing the size of the pores, without, at the same time,
choking them with solid particles : if this is not done,
and a solution mixed with a precipitate is poured into
the dry filter, some of the finely divided particles of the
precipitate are drawn into the pores by capillary attrae-
=vGoo(^lc
FILTRATION.
tion, and tend to prevent the passage of the clear solu-
tion through them. The filter shoi3d never be allowed
(^^^S>s
to reach higher than the top of the funnel, as otherwise
the weight of the liquid might cause the paper to givo
way ; and there would also
be danger of some of the
solution ruuiiing down the
outside of tlie ftmnel, after
passing through the project-
ing paper. "When the filter
is thus prepared, it may be
supported either on the ring of a retort stand (Fig. 85)
(for which the foi-m shown, at a ia very convenient), or
ou a perforated block of wood placed on the glass in-
tended to catch the filtered solution (169), the hole being
made to fit the funnel, as shown in the section (Fig. 86).
636. The solution to be filtered should be poured
gently down a glass rod (Fig. 85), so as to fall on one of
the slanting sides of the filter, and not into the apex, as
that woula endanger the bursting of the paper, and
cause splashing. When tlie whole of the mixture has
been poured on the filter, fresh water should not be
added for the purpose of washing, until the whole of
the solution has passed through ; then, by rtieanB of a
washing-bottle (94), the precipitate left on the filter is
well washed ; the current of water being applied first
towards the upper part of the filter, and directed gra-
=vGoo(^lc
ATI0N8 IN ANALYSIS.
dually downwards (Fig. 87). When the filter has been
thus nearly filled up with water, allow the whole to run
through hefore adding an\ moie, and then repeat tlie
washing, until a drop of the liltcicd liquid leaves no
fixed residue when evapoi ated and igmted on platinum
foil. If the precipitate, while standing in the filter,
cakes together into lumps, these must be broken up by
directing wpon them a strong current of water from the
washing-bottle; as otherwise the water would not pene-
trate them, and some of the soluble matter would escape
removal.
Vis. B8. 637, It is sometimes neces-
sary to keep the mixture hot
during filtration, to prevent
any of the soluble ingredients
solidifying: this may be done
very conveniently, by placing
the funnel in a zinc or copper
box of the form shown in ^ig,
88, which may be kept full of
" hot water, andboiling, if neces-
sary, over a lamp.
638. The liqmd is generally
filtered into a beaker ^ass, and
=vGoo(^lc
PILTRATIOS. 211
occasionally into flasks or dislies: it is always advis-
able to cause the stream to run gently down the side of
the vessel, and not to fall drop by drop into the centre
of the glass, as this would cause splashing and proba-
bly some loss. It occasionally happens that some of
the precipitate passes through with the filtered solution,
as may be seen in the case of freshly precipitated oxalate
of lime or sulphate of baryta. "When this takes place,
it is sometimes necessary to pass it through the filter
twice or three times before it comes through quite clear.
This may, however, in most cases, be obviated by boil-
ing the mixture before filtering, which causes the finely
divided particles of the precipitate to aggregate together.
The presence of some saline matters in solution, also,
sometimes prevents a precipitate passing through ; mu-
riate of ammonia, for example, exerts this property with
sulphate of baryta.
639. "Wheti the precipitate on the filter is completely
washed, the funnel, with its contents, is placed on a
small tripod or retort stand, on the warm sand-bath, or
near a fire, when the precipitate will gradually dry ; it
may then be separated from the filter, ignited in a small
platinum or porcelain crucible (648), (unless decompo-
sable at a high temperature), and weighed.
640. In cases where the quantity oithe pi-ecipitate is
very small, and where it will not bear a red heat with-
out decomposition, it is often convenient to use two
filters for the purpose : they should be folded up together
into the proper form, and a bole of about an inch in
diameter is then cut with scissors in the centre of the
outer one; the inner one is then clipped round the
edge, until it weighs exactly the same as tiie other, when
they will, of course, accurately counterpoise each other.
They are then again placed one inside the other, the
perforated one being outside, after which the mixture
may be filtered through them, washed, and dried. "When
dry, they are separated, and placed in the opposite scales
of the balance, when the difference in weight will give
the weight of the precipitate, that of the paper being
the same in both.
641. The precipitate may also be weighed in a single
filter, which should be placed in a covered porcelain
=vGoo(^lc
fcl
212 OPERATIONS IN ANAIjXSIS.
crucible of known weight, dried at 212°, and weighed
before the mixture is poured in. When the precipitate
on the filter has been thoroughly washed, the latter is
placed in the crucible, dried as before, and as soon as
it ia cold, again weigh-
t's' s»- ed; when the ineres^e
.. f^i in weight will, of course,
he that of the precipi-
tate,
642. Itia often neces-
sary, before weighing a
precipitate, to burn uie
^^^^^^-^^ filter containing it. Af-
^^Msffi^M^^ tor the greater part of
the precipitate baa been
removed, the filter is held with a pair of pliers, and set
fire to, over the platinum crucible in which the precipi-
tate is to be ignited, the crucible being placed in a basin,
in ease any of the ashes should fall over its sides (Fig. 89) ;
these are then collected and ignited in the crucible (648),
together with the portion of the pereipitate previousiy
removed from the filter, until the whole of the charcoal
dehved from the paper is burnt away. In cases of great
accuracy, the weight of the paper ashes, ascertained by
weighing those derived from a similar filter, must be
deducted from the gross weight ; when the paper is
good, however, it does not contain more than one to
three thousandths of its weight of inorganic matter, so
that this precaution is scarcely necessary in ordinary
643. "When a precipitate is found to subside rapidly
to the bottom of the liquid, and when it is known to be
very insoluble in water, it may be washed by decakta-
TioN, instead of on a filter, and, in many eases, this is
the more expeditious method. The mixture is placed
in an upright jar or beaker, ivhieh is tlien filled up with
water, ana allowed to stand until the precipitate has
subsided to the bottom, leaving the superincumbent
liquid clear. The latter is then removed with a syphon
(Fig. 90), or carefully poured off, and the jar again filled
up with distilled water, the process being repeated
=vGoo(^lc
EVAPORATION.
until all the soluble matter has been removed. The wet
precipitate is then placed upon a filter, or dried in a
dish, and weighed.
JEvaporafion.
643. The process of evaporation is generaliy most
conveniently effected in Berlin porcelain evaporating
basins, eitlier on a sand-bath or over a lanp, a loose
cover of filtering-paper being placed over it, if neees-
aary, to prevent particles of dust falling into the liquid.
Oare must be taken, in quantitative experiments, that
no loss is occasioned by spurting, and on this account,
it ia safer not to allow the liquid absolutely to boil.
When a saline solution has to be evaporated to dryness,
it often becomes covered, when concentrated, with a
pellicle of solid matter, preventing the escape of the
steam, which, being thus confined, occasionally causes
some of the mixture to be projected violently from the
basin. The best way of avoiding this ia to stir the mix-
ture constantly with a glass rod, from the time when
the pellicle begins to form, until it is evaporated to
dryness. ■
644. It is often ^'S'"'
advisable, and in
the case of many
liquids, as those
containing organic
matter, neeessaiy,
to evaporate over
a water-bath ; by
thismeansthe heat
is never allowed to raise higher than 212°. For this
purpose, a common saucepan, oi almost any vessel used
=vGoo(^lc
214 OPERATIONS IN ANALVSIS.
for boiling water in, may be employed, placing the dish
containing the aolntion over the top, as shown m Figure
91, eo as to expose it to the action of the steam. For
the laboratory, a convenient form of water-hath is shown
in Figure 92 ; it may he made of copper or zinc plate.
,0 8 00ji
loooo'
and the holes should he fitted with lids, to cover them
when not wanted.
646. A convenient method of drj'ing certain sub-
stances which are liable to decomposition at a slightly
ek-vatedT temperature, is to
place them under the receiver
of the air-pump (Figure 93),
over an open pan of strong
sulphuric acid; the latter ab-
Boibe the moisture which rises
Irom the substance, and a
giiduil and complete desic-
le nio ove ipi u Ac d catioii may bc effected at or-
dmarv temperatures. The
dishes oi tubes <.ontaining the substance to be dried,
may be placed on a sheet of perforated
^ * zmc lestmg on the pan of acid.- If
an ail pump is not at hand, the same
' effect miy be produced, though more
slowly by phcing the receiver in-
eloamg the substance and acid, upon
T, flit piece of glass; or the temporary
niiangement shown in Figure 94, may
be adopted abeing a beaker contain-
ing sulphmii- acid, over which the
Bubstince to be dried is suspended in
the dish e Owing to the slowness
ot the evapoiation, this method is
=vGoo(^lc
I&NIirOK.
215
well adapted for ol)taimng large and well-defined crys-
tals from saline solutions, &c.
647. IVhen a uniform temperature is required, higher
than 212°, it may be obtained by immersing tlie dish
or flask containing the substance to be evaporated, in a
bath of oil or some saline solution, the boiling-point of
which is near the desired temperature. Olive oil may
be heated to nearly 500° without suflering much decom-
position, and forms an extremely useful -bath for many
purposes, since, by regulating toe lamp, and placing a
thermometer in the oil, any lower temperature can
readily be kept up. The following list shows the boil-
ing-points of a few saturated saline solutions, which will
occasionally be found useful for this purpose : —
A saturated solution (at 60°) of
Bitartrate of Potaah,
Sulphate of Copper,
Chlorate of Polasli,
Chloride of Sodium,
Chloride of Calciiim,
Tartrate of Potash,
Muriate of Aramonii
Nitrate of Potash,
Eoohelle Salt (Tartrate of Potash and
Nitrate of Soda,
Acetate of Soda, .
boila at 214"
250°
By adding a further quantity of most of these salts
to the hot solutions, and thus making them more con-
centi-ated, considerably higher temperatures may be
obtained.
Ignition.
648. It is generally necessary, previous to weighing
a precipitate, in quantitative analysis, to heat it to
redness, in order to insure perfect dryness. This is
usually done in a weighed platinum or porcelain cru-
cible, either in a furnace or over a lamp. "When the
crucible is to be heated in the furnace or open fire, it
should be inclosed in one of earthenware, to protect it
from contact with the coals and dirt, a little magnesia
=vGoo(^lc
216 OPKI!,ATIO:SS IN ANALYSIS,
being interposed between the two (note to 580). If
the hd is made of the form shown in Figure 95, it may
) be used as a eapaale, independently of the cruci-
ble (Jig. 96).
649. When gaa is available, scarcely any otber source
of heat is necessary for the pui-pose. A email platinum
crucible may be heated to low redness over the naked
flame, resting on a small wire triangle placed on the
top of the chimney (Fig. 97).
A mixture of gaa and air, however, gives a much
more intense hea^ owing to the more perfect oxidation
of the combustible matter : such a mixture is easily
obtained by placing a small piece of wire gauze over
the chimney, and applying a light to the mixture as it
rises through the gauze (Fig, 98). The crucible may be
supported on a wire ti'iangle, or in & jacket of thin iion
plate, a (Fig. 99). In this simple manner, a very power-
ful lamp furnace is easily obtained, which may be varied
=vGoo(^lc
IGNITION.
217
in size and form to suit the purposes for which it may
be required. Thus, Mr, Hardwich and Mr. Beale have
succeeded in making a furnace admirably adapted for
heating tubes of a considei-ahle length. An ingenious
an'angement is made for gradually increasing the length
of the flame along the tube ; so that for sum purposes
as the ultimate analysis of organic substances, it may
be substituted, with gi-eat advantage, for Liebig's char-
coal furnace.
650, Mr. Solly has also contrived a veiy convenient
form of lamp, iii which he mixes air with the gas by
means of a pair of double bellows, forming a series of
blowpipe jets, the combined action of which is very
powerful, and is capable
of keeping a large pla-
tinum crucible almost
white hot for any length
of tinie. The gas pipe a
(Fig. 100) joins the tube
j, bringing air from the
bellows placed under-
neath, forming in c an
inflammable mixture ;
this bums as it issues
from the apertures in the burners, the number of which
may be multiplied to almost any extent. The crucible
may stand on a wire triangle ^.^ ^^^
resting on the circle, and the
whole may be surrounded bv a
jacket of thin iron plate to pie
vent lose of heat by radiation
651. When gas cannot le
had, the best lamp for heitmg
a small platinum eru<. hie to
redness, is that known as
Eose's, the form of which ly
shown in Figure 101 oithei
alcohol or pyroxylie spiiit ii j
be burnt in it.
=vGoo(^lc
EXAMPLES OP
Cahulation of Resulls.
652, "When the weight of a precipitate has been
ascertained, it is necesaaiy to calculate that of the con-
stituent whose weight we wish to learn, and this is
readily done according to the well-kjiown laws of com-
bination in definite proportion.*
Eor example, let ue suppose that we have to deter-
mine the percentage of eulphuric acid (SO^) in dry sul-
phate of soda (IlfaOjSOg) : we dissolve twenty grains of
the salt in water, precipitate the sulphuric acid by
means of chloride of harinm (403), and weigh the sul-
phate of baryta thus obtained : from this we have to
deduce the weight of the sulphuric acid which it con-
tains ; and lastly, to calculate from this the percentage
equivalent to it. We find the weight of the sulphate
of baryta obtained to be 32-50. Knowing the atomic
weight of sulphate of baryta (EaO,SO^) to be 117, and
that of sulphuric acid (SOg) to be 40, it is easy to cal-
culate how much of the acid is contained in 32'50 grains
of the precipitate, thus : —
,ofsulph.of Alo. wl. of BOlph. WLofsHlph-of Wl.ofsulph.a
Thus we find that twenty grains of the dry sulphate
of soda contain 11 -ll of sulphuric acid ; and we have
now only to reduce it to a percentage, to complete the
calculation, thus : —
CHAPTER II.
OP QUANTITATIVli: ANALYSIS.
653. In the following examples it is assumed that
the nature of the substances has been already ascer-
tained by a qualitative examination ; since it is always
* See Pownps' "Manual of CliemiBtrj," p. 18T, et seq.
siGooi^le
neeessaiy, before proceeding to estimate the consti-
tuents of a compound, that we should know what those
oonstituents are.
QiiuiitiUitiee Anali/sis of Sulphate of Ct/ppoi:
(Cu6,SO,-)-5Aq.)
Estimate the quantity of oxide of copper (CuO), sul-
phuric acid (SO3), and water (HO), in sulphate of
copper.
(1.) £stimatwu 0/ the Oj:ide uf Coppur.
654. Dissolve twenty grains of the salt in eight or
ten ounces of water, in an evaporatinff basin, and
gently boil the solution. Add to it, while boiling, a
solution of caustic potash in slight excess, which will
throw down the black oxide of copper (870).
CuO,SO,-^EO=-CxxO-irKO,SO^.
The mixture is poured upon a filter (636), and care-
fully washed with boiling water, until the whole of the
soluble matter is removed. The precipitate in the filter
is then dried, separated from the filter, ignited, and
weighed.
When the precipitate consists, as in this case, of the
substance whose weight we wish to ascertain, uucom-
bined with other matter, we have only to reduce the
amount thus obtained, to a percentage : —
20 : wci^lil or Ihs precipitole of oxide : : 100 : ic = : pefc=iit;ige of oxide of cop-
per. Or, 111 olher words, mulliply ihe weiglit tiy 6.
(2.) Estimation of the. Sulphuric Acid.
655. The acid maybe estimated either from the same
portion of the substance as was used in determining the
oxide (in which case the solution filtered from the pre-
cipitated oxide must be concentrated by evaporation
(644)), or afresh portion of the salt may be used. The
latter method is in this case the simplest.
656. Dissolve twenty grains of the sulphate in water
as before, acidify it with a few drops of nitric acid, and
=vGoo(^lc
220 EXAMPLES OE
add a solution of chloride of bariam (BaOl) as long as
it eauaes auy precipitate. Sulphate of baiyta (BaOjSOs)
is thus thrown down (403), and the whole of the sul-
phuric acid is in this way removed from the solution.
As the mixture in its present state would notfilterwell
(638), it ia advisable to boil it before filtering, when it
will be found that the eolntion will pass through clear.
The precipitate is well washed with hot water on the
filter, dried, ignited in a platinum or porcelain crucible,
and weighed. Then, knowing the atomic weight of
sulphate of baiyta to be 117, and that of sulphuric acid
(80,) to be 40, or, in other words, that every 117 parts
of the former contain 40 of the latter, it is easy to cal-
culate the quantity of sulphuric acid contained in the
precipitate, thus : —
117 : *0 ; . w«gbt of,he pr.cipi..te : « = J "^^ ""^Yptl^o 'coW^r^'""" "'}
which number, multiplied by five, will represent the
percentage of sulphuric acid in crystallized sulphate of
copper.
(3.) Estimation of the Water.
657. Tlie water is estimated by heating 20 grains on
the sand-bath in a counter[3oised crucible, at a tempera-
ture of about 400°, until it ceases to lose weight : in
this way the water ia expelled, and its quantity is shown
by the loss of weight, which, when multiplied by five,
will give the percentage of water,*
SECTION II.
Quantitative Anaii/sis of Chloride of Polassiuni (KCl).
Estimate the quantity of potassium and chlorine in the
chloride.
(1.) Estimation of the PolassiuTii.
658. Dissolve twenty grains of the salt in as Small a
* When the q^nnntitj of water has to be estimated in salts which can.
not hear the necessary heat without the Tolatiliaatioii of a portion of
Hamr acicl, the salt should be intimately mixed with five or six times
ita weight of protoxide of lead, or some other strong base, before expo-
sure to heat : this combines with, and fixes, any of the atid iiat may
be disengaged fmrn the other base.
=vGoo(^lc
QUANTITATIVE ANALYSIS. 221
quantity of water as possible, iu an evaporating basin ;
add bichloride of platinum to the solution, and evapo-
rate the mixture to dryness on a water-bath (645).
Treat the residue with alcohol, to dissolve out the excess
of the bichloride, and wash the insoluble double chloride
of platinum and potassium (185) with fresh alcohol, on
a weighed filter (641). If it is found that the alcohol
which is added to the evaporated residue, does not be-
come sensibly colored yellow, it is owing to there being
no excess of chloride of platinum present ; that salt
having been added in too small q^uantity. In this case,
a little more chloride of platinum should be added, and
the mixture again evaporated as before, and subsequent-
ly ti-eated with alcohol. The precipitate is then dried
on the filter, at a moderate heat, and weighed.
659. The atomic weight of the double chloride (KCI,
PtOlj) being 247, and that of potassium being 40, we
deduce the quantity of potassium contained in the
twenty gi'ains of the chloride, thus: —
and lastly, it is reduced to a percentage, thus : —
or the same result may be obtained by multiplying hy
five.
(2.) Estimation of the CMorine.
660, Twenty grains of the chloride are dissolved in
three or four ounces of water, as before ; the solution
is then heated, acidified with a few drops of nitric acid,
and treated with a solution of nitrate of silver, as long
as it causes any precipitate (429, 633).
KCl-^AgO,NOi=iLgC\-^EO,NO>,.
The mixture is then boiled for a few minutes (as other-
wise a portion of the precipitate would pass through
the pores of the paper (638) ) and filtered. The precipi-
tated chloride of silver is thoroughly washed with ms-
tilled water on the filter, and dried ; it is then removed
from the paper, and gently ignited in a counterpoised
porcelain crucible, until it fuses into a waxy mass, and
=vGoo(^lc
661. The atomic weight of chloride of silver is 144,
and that of chlorine 36, so that we deduce the weight
of the chlorine from that of the chloride, thus : —
Then, for the percentage, multiply by five.
SECTION III.
Quantitatise Analysis of a mixture of Sulpliateof Copper
CCuO,803+5Aq) and Chloride of Sodium (NaCl).
Estimate the quantity of oxide of copper (CuO), sodium,
sulphuric acid (SO3), chlorine, and water in the
mixture.
(1,) Estimation of llio Water.
662- The water is estimated in the manner described
in paragraph (057).
(2.) Estimation of (lie Oxide of Copper.
663. Dissolve twenty-five grains of the mixture in
water, acidify the solution with a few drops of hydro-
chloric acid, put it into, a beaker, and pass through it a
stream of hyurosulphurie acid, until it is saturated (701) ;
the whole of the copper is in this way thrown down as
sulphide (368). Filter, and wash the precipitate with
distilled water, which should contain in solution a little
hydrosulpburic acid, as otherwise a trace of copper is
liable to become oxidized and dissolved. The clear
solution, together with all but the last washings, is set
aside for subsequent examination (664). The washed
precipitate of sulphide of copper is now for the most
Eart separated from the filter, which latter is to be
urnt, and the ashes added to the rest of the precipi-
tated sulphide. The precipitate, containing the whole
of the copper, is then digested in strong nitric acid,
until the whole of the precipitate is dissolved, or until
nothing remains undissolved but a little sulphur, of a
pale yellow color. The acid solution thus obtained is
diluted with water, and filtered, if necessary, from the
=vGoo(^lc
QUAHTITATIVE ANALYSIS. 223
undiseolved sulphur. The whole of the copper is now
contained in the solution as nitrate. The copper is
next to he thrown down as oxide hy potash, dried and
weighed, in the manner already described (654), The
percentage is calculated ae follows : —
25 : wL of oxide obtained : ; 100 ; perceiUage of ojiide of copper in tlie miiinre.
Or, as 26 i« llie fourth pan o( 100, Ihe same rasull is nrtived at by eimply multiplying
the weigh! of the oxide obtained, by 4.
(2.) Bslimation of the Sodium.
664. The chloride of sodium contained in the solution
filtered from the sulphide of copper, is concentrated by
evaporation, and then converted into sulphate of soda
(NaO,SOg), by evaporating to dryness with a slight
excess of strong sulphuric acid.
The residue is gently ignited in a counterpoised covered
crucible, in which a fragment of carbonate of ammo-
nia is suspended by means of a stiip of platinum foil,
and weighed; the weight of the sodium is thus calcu-
lated : —
which when multiplied by four, gives the percentage
of sodium.
(3.) JSgHinafion of the SidpJmrtc Acid.
665, A second portion of twenty-five grains of the
mixture is dissolved in water, for the purpose of esti-
mating the sulphmie acid and chlorine.
Add to it first, a solution of nitrate of baiTta, as long
as it causes any precipitate, and boil the mixture for a
few minutes to prevent any of tie finely divided sul-
phate of baryta passing through the filter (638). The
precipitate is washed, dried, and weighed, the clear
solution being reserved for estimating the chlorine (666) ;
the quantity of sulphuric acid is then calculated in the
manner already described (656), twenty-five being sub-
stituted for twenty in the calculation.
=vGoo(^lc
(4.) Estimation of the OMorine.
666. The solution filtered fi-om the sulphate of baryta
(665), together with the first washings, is heated in an
evaporating hasin, over a lamp, and treated with nitrate
of silver as long ae it causes any precipitate (429). The
chloride of silver thus formed is filtered, dned, and
weighed ; and the weight of the chlorine deduced from
it in the manner described in (660), twenty-five being
substituted for twenty in the calculation.
Thus the percentage of oxide of copper, sodium, sul-
phuric acid, chlorine, and water, will have been ascer-
tained.
SECTION IV.
Quantitative Analysis of a mixture of Sulphate of Zinc (ZnO,
SOj+TAq) and Carlonate of Baryta (BaO,CO,).
Estimate the quantity of water, sulphuric acid, oxide of
zinc, carbonic acid, and baryta, in the mixture.
667. Twenty grains of the mixture ai'e to be boiled
with three or four ounces of water, which will dissolve
out the sulphate of zinc from the carbonate of baryta.
The mixture is filtered, and the insoluble portion washed
until the washings leave no residue when evaporated
on platinum foil. The solution contains the whole of
the sulphate of zinc, while the carbonate of baryta re-
mains undissolved ; the latter is retained for subsequent
examination (671).
(1.) Estimation of the Oxide of Zinc.
668. The solution is treated with carbonate of potash
as long as it causes any precipitate, and then boiled.
The zinc is thus thrown down as a basic carbonate (257) ;
the precipitate is washed on a filter, dried, and ignited,
when the water and carbonic acid of the compound are
expelled, and pure oxide of zinc (ZnO) remains, which
is weighed ; the weight thus obtained, multiplied by
fi've, gives the percentage of oxide of zinc.
=vGoo(^lc
QUANTITATIVE ANALYSIS. 225
(2.) Estimation of the Sulphuric Acid;
669. The solution filtered from the precipitated car-
bonate of zinc, is now supersaturated with nitric acid,
and boiled to expel the carbonic acid; chloride of
barium ia added, and the mixture ia boiled for a few
minutes to clarify it (638) ; the sulphate of baryta thus
obtained is washed, dried, ignited, and weighed as
ah-eady described (656), and the weight of the sulphuric
acid which it contains, calculated as before.
(3.) Estimation of the Water.
070. The water may be determined by beating the
mixture on the sand-bath, as described in (657).
(4.) Estimation of the Bavyta.
671. The residue which was insoluble in water (667),
is now removed from the filter into a small beaker, and
dissolved in dilute hydrochloric acid, a gentle heat
being applied, if necessary. In this way, the carbonate
is decomposed, carbonic acid ia given off, and chloiide ■
of barium remains in solution.
BaO,COa+ffCi=Baa-i- ffO+CO,.
The solution thus obtained is treated with dilute sul-
phuric acid, as long as any precipitate is produced, and
then boiled : the precipitate is separated by filtration,
washed, dried, ignited, and weighed.
The atomic weight of sulphate of baryta being 117,
and that of baryta being 77, the quantity of the latter
in the- precipitate is calculated ae follows : —
(Wi.ofbarytiiconlain8d )
117:7T::wl.Dfsulphaleofborylaoblsiiied: j inaOBfaUis of Ilia mix- \
(5.) Examination of the Oarbonic Add.
672. The carbonic acid is estimated hj decomposing
the carbonate with hydrochloric acid in a flask, and
determining the amount of loss, as described in para-
graph (174).
=vGoo(^lc
EXAMPLES OP
Quantitative Analysis of Magneiian Limestone; cohsisling of
Carbonate of JAme (CaO,COa), Carbonate of Mag^nesiaQS.^,
OOJ, Peroxide of Iron (Befi^, a Utile Silica (SiOb), and
■moisture.
Determine the quantity of lime, magnesia, peroxide of
iron, carbonic acid, silica, and moisture, in magnesian
limestone. Reduce about 100 grains of the mineral
to moderately fine powder,
(1.) Esfimatimt of the St/yroscopie Moisture.
673. "Weigh fifty grains of the pounded mineral in a
small counterpoised crucible or evaporating dish, and
dry it on a water-hath, or on the hot part of the sand-
bath : weigh it at intervals of a quarter or half an hour,
until it ceases to lose weight (630). The losa will be
the quantity of moisture m fifty grains, which, when
multiplied by two, will give the percentage.
(2.) Estimation of the Silica.
674. "Weigh twenty-five grains of thepounded mineral
in a countei'poiaed flask, moisten it with a little water,
and add dilute hydrochloric acid in small quantities, to
avoid too violent efl'ervescence (419). "When the greater
part is dissolved, warm it with a little fresh acid, which
will dissolve everything but the small quantity of silica.
The mixture is now filtered, and the precipitate
thoroughly washed, the solution being retained for
subsequent examination (675) ; the filter containing the
precipitate is then ignited and weighed. The weight
of the siliceous residue, multiplied by four (25x 4=100),
gives the percentage of silica in the stone.
(3.) Estimation of the Peroxide of Iron.
675. The acid solution filtered fi-om the siliceous
residue, is now neutralized with ammonia, and a few
drops of hydrosuiphatc of ammonia are added, which
will throw down the iron as the black sulphide (279).
=vGoo(^lc
QtTANTITATIVE ANALYSIS. 227
This is to be filtered and carefully washed, the solution
being retained tor farther examination (676) ; when the
whole of the aoluble matter is removed, the filter, with
the moiat precipitate, is digested in hydrochloric acid,
until the black sulphide is entirely decomposed, and
nothing but sulphur remains uiidisaolved. The solu-
tion is now diluted, and eepaitited by filtration from
the sulphur and fragments of the first filter, which
must be well washed to remove the whole of the soluble
matter. The solution is well boiled to expel the hydro-
sulphuric acid, and then heated with a little nitric acid,
for the purpose of peroxidizing the iron. Ammonia is
BOW added m slight excess, which precipitates the whole
of the iron as hydrated peroxide (280). The precipitate
is filtered, dried, ignited, and weighed. The weight,
multiplied by four, gives the percentage of peroxide of
iron in the mineml.
(4.) Estimation of the Lima.
676. The solution filtered from the sulphide of iron,
is now to be boiled with a alight excess of hydrocMorie
acid, to decompose the excess of hydrosulphate of am-
monia, and expel the hydrosulphuric acid : when the
smell of that gas is no longer perceptible, filter the
solution, if necessaiy, from any sulphur that may have
been precipitated, and neutralize the clear solution
with ammonia ; after which add oxalate of ammonia as
long as it causes any precipitate (633). This thi'ows
down the lime as oxalate (218), while the magnesia re-
mains in solution, not being precipitated by oxalate of
ammonia ia the presence of muriate of ammonia, which
is contained in the solution. The mixture is boiled
(638), and filtered, and the precipitate washed and
dried ; the solution being retained for subsequent ex-
amination (677). The oxalate of lime is now removed
from the filter, and ignited, by which means it is de-
composed, and converted into carbonate of lime : at a
red heat, however, a portion of the newly formed car-
bonate is decomposed, the carbonic acid being expelled,
and thus leaving a little caustic lime (CaO) mixed with
the carbonate. When cool, it is moistened with a
=vGoo(^lc
228 EXAMPLES OP
solution of carbonate of ammonia, and again gently
heated, to expel the excess of carbonate of ammonia :
the whole of the lime is thus converted into carbonate,
in which state it is weighed.
The atomic weight of carbonate of iimo being 50,
and that of lime 28, the weight of the latter is thus
calculated : —
BO-aa--wtofcnrl.o.ialeobtamed ■ S Wl. oflime conloincd in 35 >
which number, multiplied by four, gives the percentage
of lime.
(5.) Estimation of the Magnesia.
677. The solution filtered from the oxalate of lime is
now to be concentrated by evaporation, and treated
with a mixture of phosphate of soda and a considerable
excesB of oaustic ammonia ; when the mixture ia set
aside for a few honrs, being stuTed at intervals with a
flass rod. The magnesia is thus thrown down as the
ouble phosphate of ammonia and magnesia (206).
Before filtering, a little of the mixture should be tested
with a few drops more phosphate of soda, and allowed
to stand a short time ; when, if no fresh precipitate is
formed, it may be concluded that a sufficient quantity
of the precipitant has been added.
The mixture is now filtered, washing always with
water containing a little free ammonia, as the double
phosphate is slightly soluble in pure water (any of the
precipitate that adheres to the sides of the glass being
separated by means of a feather, which must be well
washed from all adhering particles), and the precipitate,
after drying, is ignited in a small counterpoised plati-
num or porcelain crucible, and weighed. During igni-
tion, the double phosphate ia decomposed into phos-
phate of magnesia (2MgO,POs), the water and ammonia
being driven off (206).
The atomic weight of the phosphate of magnesia thus
formed, being 112, and that of magnesia 20, the quan-
tity of magnesia contained in the precipitate is thus
calculated i —
=vGoo(^lc
QUAN'TITATIVB ANALYSIS. 220
Ha : 40' :: "1. of pliosphala : wt, of masiiesiB in 2S B"- of Iha miiietal,
wliich when multiplied by foar, gives the percentage of
magnesia in the mineral.
(G.) Estimation of the Carbonic Acid.
678. The carbonic add is estimated in the manner
described in paragraph (174).
679. Thus we shall have determined the percentage
of the —
Water, .....
Peroxide of iron, ....
Magnesia, .....
Carbouic acid, ....
100-00
which when added together, ought to amount to about
99 or 99-5 ; and the small deficiency, always inevitable
in such analyses, is put down as "loss," to make up the
100 parts.
SECTION VI.
Quantitative AnaJj/nis of Copper Pi/rites ; consisting of Coj)per,
Iron, Sulphur, Silica (Quarte), and moisture.
Determine the quantity of copper, iron, sulphur, silica,
moisture in copper pyrites.
(1.) Eiiimation of the Moisture.
680. Dry 100 grains of the pounded pyrites on the
sand-bath, in a counterpoised crucible or dish: the loss
is the percentage of moisture.
681. Boil 33-33 grains of the pounded mineral in aqua
regia (698) until the sulphur which remains undissolved,
eoTleets into a yellowish porous. lump. Dilute the acid
mixture with two or three times its bulk of water ; filter,
and wash the insolnhie residue (coneieting of sulphur
'40 = 20x2; becausR each equivalent of the pliospliate (2MgO,P05)
■ ' equivalents of magnesia.
20
=vGoo(^lc
230 EXAMPLES OF
and silica) until the whole of tlie soluble matter is sepa-
rated from it (636) ; reserve the insoluble residue for
further examination (684),
682. As the nitric acid present in the aq^na regia,
would interfere with the action of the hydroaulphurio
acid made use of in a subsequent stage of the analysis,
it should be expelled by evaporation with a slight excess
of hydrochloric acid (562).
(2.) Estimation of the Sulphur.
683. A portion of the sulphur will have become oxi-
dized by the action. of the nitric acid in the aqua regia;
and the sulphuric acid thus formed, will be contained
in the filtered liquid, in combination with the oxides of
copper and iron.
Add chloride of barium to the solution aa long as it
causes aprecipitate (403) ; boil the mixture ; filter, wash,
and ignite the precipitate. From the weight of the sul-
phate of baryta thus obtained,, that of the sulphur from
which the Bulphurie acid was dei-ived, may be ascer-
tained by the following calculation: —
684. The weight of the sulphur which resisted the
action of the aqua regia (681), must now be estimated.
The undissolved residue is to be thoroughly diied at
212°, and weighed: it is then gradually heated to redness
in a counterpoised or weighed porcelain crucible, until
the whole of the sulphur is burnt ofl", when it must be
again weighed, the loss during ignition being of course
the sulphur. This weight must be added to that already
deduced from the sulphate of baryta (683), which, to-
gether, will give the quantity of sulphur contained in
33-33 grains of the mineral, or one-third of the per-
centage.
(3.) Estimation of the Silica.
685, The siliceous matter is left after the expulsion
of the sulplmr, by ignition, from the residue insoluble
=vGoo(^lc
QUANTITATIVE ANALYSIS. ilrfi
in aqua regia.' The percentage ia obtained by nmlti-
plyhig hy three.
(4.) Eetimalion of the Copper.
%'&Q. The solution filtered from the sulphate of baryta
(683), containing a slight excess of chloride of barium,
18 now treated with a slight excess of sulphuwe acid, to
remove the superfluous baryta, which ia separated by
filtration. The clear liquid is then subjected to a cur-
rent of hydrosulphurie acid gaa as long as any precipi-
tate ia produced, and filtered. The sulphide of copper
thus formed is treated In the manner described in (663),
and from the weight of the oxide (CuO), that of the
copper is calculated thua: —
which, when multiplied b;? three, represents the per-
centage of copper in the mineral.
(5.) Estimation of the Irort.
687. The solution filtered from the sulphide of copper,
must now be boiled to expel the excess of hydrosul-
phurie acid, filtered, if necessary, from aulphur, and
afterwards heated with a little nitric acid, for the pur-
pose of peroxidizin^ the iron (269). Ammonia is added
m alight excess : this throws down the iron as hj^drated
peroxide (280), which is to be filtered, dried, ignited,
and weighed. The weight of the iron contained in the
precipitate is thus calculated : —
Alp. WL of peroiiile Alq. wl. Wt, of oiide Wl. of iron conlnined in
,. ^ ., j'ounii in the pjrites, and will be con-
tained in this residue as peroxide (SnOj)- It maj be detected bj the
blowpipe (3T9), and if found to be present, the residue is boiled witli
hydrochloric aeid to dissolve out ibe minute globules of metallic tin ;
the chloride thus formed (SnCl) ia filtered, and converted into peroxide
by boiling with nitrie aeid ; the excess of acid is then expelled by evapo-
ration, when the peroxide of tin, if present ia Enfficient quantity, may
be weighed, and its weight dednctea from tbat of the siliceous residue.
=vGoo(^lc
232 EXAMPLES 01' QUANTIIATIVB ANALYSIS.
688. The quantities thus obtained, should, when added
together, amount to a fraction less than 100, the defi-
ciency being, as before, set down as " loss" : —
=vGoo(^lc
PART V.
EBAQESTS.
689. The following is a
usually employed in testing
Sulphuric acid, stvong and I
Hydrochloric acid.
Nitric acid.
Nitrolijdrodiloric acid
Oxafic acid.
Acetic acid.
Tartaric aeid.
Hjdiissiilphuric acid (
retted hjdrogen).
Hydros nlphate of a
Carbonate of ammc
Oxalate of ammonia.
Phosphate of soda and an
Catbonata of potash.
Nitrate of potaah.
Iodide of potaBeium.
Chromate of poiash.
Cyanide of potassinn:
PejTOcjaiiiae of potaf
lowpraasiate of poiash).
Ferridoyanideof potassium (red
pruasiate of potash).
690. Most of tliese
always
B (yel-
1 commerce,
list of the
and analysis
Antimoniate of potash.
Carbonate of soda.
Phosphate of soda.
Sulphate of lime.
Chloride of caliiinm.
Chloride of bariuro.
Nitrate of haryta.
Perchlovide of iron.
Nitrate of cobalt.
Sulphate of copper.
Ammonio-sulphate of copper.
Acetate of lead.
Subaeetats of lead.
Nitrate of eilver.
Ammonio-nitrate of silver.
Perchloride of mercury.
Protochloride of tin.
Perchloride of gold.
Bichloride of platinum.
Sulphate of indigo.
Solution of starch.
Black flux.
Distilled water.
Alcohol.
Litmus and turmeric paper.
, as they are met with
more or less impure ; and,
=vGoo(^lc
234 REAGENTS.
as those even which are sold in the shops as pure rea^
fents, are not unfrequently found, on examination, to
e otherwise ; it is always necessary, before talking a
reOrgent into use, to ascertain by experiment whether it
is of sufficient purity for the purposes for which it is
intended. It may be stated as a general rule, that, when
a chemical substance is required for use in analysis, it
ought to be as nearly pure as possible ; while, for the
other operations of chemistry, the substances which are
usually met with in commerce are sufficiently pure.
The following brief remarks relative to the more com-
mon impurities of reagents, together with their princi-
pal uses, will probably bo found useful to the student.
Sufphuric Acid {nO,SO,').
691. Sulphuric acid, as found in commerce, is never
Eure. The most common impurities are sulphate of
3ad (PbO,SO^), nitric acid (iVOj), or binoxide of nitro-
gen (iVOj), and occasionally arsenic, and other saline
matters.
(a) If it contains the first, it will become turbid when
diluted with four or iive times its bulk of water, owing
to the sulphate of lead, which is soluble in the strong
acid, being insoluble in the dilute.
(6) Nitric acid, or the binoxide of nitrogen, is detected
by warming a little of the acid in a test-tube, with a
small crystS of protosulphate of iron (449) ; or by boil-
ing a small portion tinged with a solution of sulphate
of indigo, when, if nitric acid is present, the blue color
will disappear (452).
(c) Arsenic may be detected by Marsh's test (318).
(d) Any fixed saline impurity remains as a residue
when a few drops of the acid are evaporated on platinum
foil.
692. The uses of sulphuric acid are very numerous.
Besides being employed extensively in many branches
of manufacture, it is used in the laboratory as a power-
ful decomposing agent ; owing to its strong affinity for
bases, nearly alTs^ine compounds are decomposed by
it, and its solvent powers are also very great. It is often
employed for the purpose of decomposing organic mat-
=vGoo(^lc
RBA«ENI8. 5i35
ter ; also in the preparation of hydrogen, liydrosul-
phuric acid, and other gases ; as a test for certain metala,
and for many other purposes.
693. "When dilute sulphuric acid is required, it is pre-
pared by mixing together, iu a poreelaiu basin, one part
of the strong acid with four parts of distilled water,
always adding the acid to the tvater, which should be kept
constantly stirred, and allowing the precipitated sul-
phate of lead (if any) to subside, after which the clear
liquid may be poured off.
HydrcKhhrk Add (HCl').
694. This acid, in the form met with in commerce, is
never pure, usually containing sulphuric acid and
chloride of iron, and occasionally free chlorine and
ti'aces of arsenic.
(a) Evaporate a drop or two on platinum foil : if pure,
no residue is left.
(6) Dilute a portion with four or five times its bulk of
distilled water, and add a drop of chloride of barium :
if eulphurie acid is present, a white precipitate is pro-
duced {403, 428).
(c) Add ammonia in excess : a brown precipitate in-
dicates iron (280).
{d) Boil a little of the acid, tinged with sulphate of
indigo : if it contains free chlorine, the blue color is
bleached.
{e) Arsenic may be detected by Marsh's test (313).
695. The uses of hydrochloric acid ai-e very numer-
ous, especially in analysis, in which it is of constant
value as a solvent for substances which are insoluble in
water; n^ost of the metals dissolve readily in it, form-
ing soluhle chlorides, and it is occasionally used to pre-
cipitate silver and mercury from their solutions.
When dilide hydrochloric acid is required, the strong
acid may be diluted with about twice its bulk of water.
mtric Acid {HO,NO^.
C96. N^itric acid, as met with in commerce, usually
contains sulphuric and hydrochloric acids, and occa-
sionally a little fixed saline matter.
=vGoo(^lc
(«) T!ie latter may be detected by evaporating a few
drops on platinum foil, when any fixed impurities will
be left.
Dilute a little of tlie acid with water, and divide it
into two portions.
(6) To the first, add chloride of barium ; if a white
precipitate is produced, sulphuric acid ia present (403,
445).
(e) To the other, add nitrate of silver ; a white pre-
cipitate, soluble in ammonia, indicates hydrochloric
acid (429).
697. l^itric acid is used ehiefiy as a solvent for sub-
stances which are insoluble in water, especially some of
the metals, which it readily oxidizes, and converts into
nitrates, nearly all of which are soluble in water. It is,
also, frequently employed to raise compounds to a
higher state of oxidation, as in converting the protoxide
of iron {FeO) into the peroxide {Fe^O^.
"When dilute nitric acid is required, it may be pre-
pared by mixing one part of the strong acid with two
parts ot distilled water.
NUrokydroehloric Acid (^Aqna Regia).
698. This is always prepared when required, by
mixing together strong nitric and hydrochloric acids,
usually in the proportion of one part of nitric to four
of hydrochloric. Its chief uses depend on its intense
oxidizing or chlorinizing properties, whereby the most
refractory metals, some of which resist the action of all
other aeida, are brought into solution.
Hi/drosulpkuric Acid (HS). (^Sulphuretted Hydrogen.')
699. This reagent, whether required in the gaseous
form or in solution, ia always prepared in the laboratory.
Fragments of sulphide (sulphuret) of iron (FeS) are
placed in a bottle, a (Fig. 102), and treated with dilute
sulphuric acid (which for this purpose should consist
of one part of acid and eight parts of water), which dis-
s the gas.
FeS-|-H0,S0a=R0,S0.+n8.
=vGoo(^lc
The gae thus formed, is passed througli water contained
in the eeco d bottle b to tl e i pee ot i urifyiiig it
from an-\ Iphur e ac d in 1 ron thit mi have been
cari'ied ovei mechan cilly and r then co ducted, by
the bent t ibe / into i bottle of d et lied -n ater, when
an aqueous solut on of the "-18 Tequiel orintoajar
containing any solution wTiich it is intended to act
upon (95).
It must be borne in mind, when experimenting with
this gaa, that it is not only highly offensive, l)ut poison-
ous, and induces headache and nausea even when largely
diluted with air : on this account it should be prepared
either near a ventilating flue, or in the open air; never
in a close room.
700. In most cases of mere testing, the aqueous solu-
tion is the most convenient form in which to apply it.
The water should be saturated with the gas, of which
it is capable of retaining in solution about its own
volume; this may be judged of by its strong disagree-
able smell, resembling that of rotten eggs, and by its
giving a copious white precipitate of sulphur when
treated with porchloride of iron (278). It should also
be tested for iron, which it sometimes contains when
carelessly prepared ; if such is the case, it becomes dark
colored on the addition of ammonia, owing to the
formation of sulphide of iron (271). The solution
should not be kept long, as it is liable to decompose,
unless carefully closed from the air, the oxygen of which
combines with the hydrogen to form water (SO),
while sulphur is deposited.
=vGoo(^lc
701. "When it is required to precipitate, by hydroaul-
phuric acid, the whole of any metal in a solution, it is ne-
cessaiy to pass the gaa at once into it ; and tliia should be
continued until the liquid is saturated, which is known
by removing the gas-delivering tube, and blowing away
the superincumbent air ; when, if it smells distinctly of
the gaa, the solution may be considered eatui-ated, and
the whole of the metal must have been converted into
sulphide.
702. The important uses to which hydrosulphuric
acid is applied, render it of great value in many pro-
cesses of analysis. It precipitates many of the metals
from their solutions as insoluble sulphides ; and is one
of the reagents employed in detennining the class to
which an unknown metal in solution belongs ^179).
It is also extensively used in quantitative analysis, on
account of the perfect manner in which it separates the
whole of many of the metals from their solutions. Hy-
drosulphuric acid is also sometimes useful as a deoxidiz-
ing agent, reducing metallic oxides in solution to a
lower degree of oxiaation, aa the peroxide of iron to the
protoxide ; this property is owing to the facility with
which it is decomposed, yielding up its hydrogen to the
oxygen of the oxide, while the sulphur is usually set
free (278).
Oxalio ^ci(^(HO,C,0,).
703. Oxalic acid oceaaionally contains traces of nitric
acid (which causes it to deliquesce in damp air, and to
have a slightly acid smell), and also fixed saline matter.
(a) The first may be detected by boiling the solution
with a drop or two of sulphate of indigo (452).
iP) The fatter, if present, is left as a fixed residue after
ignition on platinum foil.
It may be easily purified by recn'stallization.
704. The chief use to which oxalic acid is applied in
analysis, is to precipitate lime from its solutions (218).
(See also Oxalate of Ammonia (714). ) For use as a test,
one part of the crystallized acid may be dissolved in ten
parts of water ; but, as the solution is liable to decom-
pose, it is better to keep it in the solid state, and to dis-
solve a little when wanted.
=vGoo(^lc
EEAQBNTP. 26))
Acetic Acid (JIO,C\ff^O^).
705. This acid m often contaminated with one or
more of the following substances: sulphuric, sulphu-
rous, hydrochloric, and nitric acids, lead, and other
saline matter.
(a) Any fixed impurity may be detected by heating
a little on platinum foil.
(6) Add to a portion of the diluted acid, a solution of
chloride of barium : if sulplmric acid is present, a white
precipitate, insoluble in nitric acid, is thrown down (403).
(e) Eoil a little of the acid with a very small quantity
of peroxide of lead (Pb304) : if the latter becomes white
(owing to its conversion into sulphate of lead), sulphur-
ous acid is present. 'Phfi^+SO^=F'bO,SO^+2PbO.
(d) Nitrate of silver, added to the diluted acid, gives
a white curdy precipitate, which is insoluble in nitric
acid, if any hydrochloric acid is present (429),
(e) Boil a little of the acid, tinged with sulphate of in-
digo : if the color is bleached, it is probably owing to
the presence of nitric acid (452).
(/) Neutralize a small portion with ammonia, and add
hydrosulphuric acid or hydi-osulphate of ammonia : if
lead or any other metallic matter is present (except the
alkalies and alkaline earths), a precipitate is produced
(648).
706. Acetic acid is chiefly employed in the laboratory
as a solvent, and for the gui'pose of acidifying solutions,
in cases where hydrochloric and nitric acid would act
prejudicially.
Tartaric Acid C2HO,0,H,0„).
707. Tartaric acid sometimes contains a trace of lime
and sulphuric acid, but is usually sufficiently pure for
analytical purposes. The lime may be detected by neu-
tralizing a portion with ammonia, and adding oxalate
of ammonia (218) ; and the sulphuric acid by chloride
of barium (403).
708. Tartaric acid is used as a test for potash, with
which it forms a spaiingly soluble hitartrate (186). Its
propoi-ty of preventing the precipitation of iron and
=vGoo(^lc
240 11 K A E N T S.
some other metals by the alkalies (478), is occasionally
made available in analysis. It should be kept in a solid
state, and a solution made when required, as when kept
in solution it soon becomes mouldy ; for this purpose,
the ciTstallized acid may be dissolved in about three
times its weight of water.
Ammonia (Nff^).
709. The liquid ammonia of the shops is generally
suiEciently pure for mostpui-posea of analysis; it some-
times, however, contains traces of carbonate, sulphate,
and muriate of ammonia, and occasionally chloride of
calcium. The carbonate is detected by adding lime
water (420) ; the sulphate by supersaturating with dilute
nitric or hydrochloric acid, and testing with chloride of
barium (403) ; the muriate of ammonia maybe detected
by superaaturating with nitric acid, and adding nitrate
of ailver (429) ; and the lime (chloride of calcium) with
oxalate of ammonia (218).
Ammonia is used chiefly for the purpose of neutraliz-
ing acid solutions, and for precipitating metallic oxides
from their solutions, most of which are decomposed
by it.
Hydroiulpliate of Ammonia (NH,S,HS)-
710. Hydrosulphate of ammonia is prepared by pass-
ing a stream of hydrosulphuvic acid gas (699) through
a solution of ammonia until H is saturated. To ascer-
tain whether the saturation is complete, a few drops
may be tested with sulphate of magnesia ; if the am-
monia is saturated, this gives no precipitate ; but if any
free ammonia is left, it throws down the hydrate of
magnesia. When first prepared, the solution is almost
colorless, but it gradually becomes yellow, owing to
partial decomposition, the oxygen of the air combining
with the hydrogen, while sulphur is set free, and re-
mains dissolved: when this decomposition has taken
{dace, the addition of an acid causes not only the evo-
ution of hydroeulphurie acid, but also precipitates the
dissolved sulphur (440).
711. Hydrosulphate of ammonia is much used, both
=vGoo(^lc
RKAGBNTa.
in qualitative and quantitative analysis, chiefly for the
purpose of precipitating certain metals from their solu-
tions, and for separating the metala of the third class
from the alkalies and alkaline earths (593).
Garbonalc of Ammonia (2NH,O,300,).
712. The common carbonate of ammonia is a sesqui-
carbonate, or a compound of the neutral eai-boiiate
(NH^O.CO^) and the bicarbonate (^£^0,200,). When
the neutral carbonate is required, aud it is the beat suited
for most purposes of analysis, it may be prepared in
solution by dissolving one part, by weight, of the crys-
tallized sesquicarbonate, in three or four parts of water,
and adding one part of liquid ammonia {sp. gi'. 0-96).
It is frequently employed in analysis, to precipitate some
of the metala as carbonates : it is also used to neutralize
acid solutions, and for other purposes.
713. It is occasionally contaminated with traces of
animal oil, and sulphate and muriate of ammonia.
(a) Heat a small fragment on platinum' foil : if any
fixed saline impurity ie present, it will be left after igni-
tion ; and if any charring takea place, it indicates the
presence of animal matter.
(6) Supei-saturate a little of tlie solution with nitric
acid, and add to one portion a few drops of chloride of
barium : a white precipitate, insoluble in nitric acid,
indicates sulphuric acid (403).
(e) To the other portion of the acid solution, add
nitrate of aUver : if any muriate of ammonia is present,
it will cause a white curdy precipitate (429).
Oxalate of Ammonia {NH,0,CjO,+Aq).
714. This salt, as metwitli in the shops, is
pure for all purposes of analysis. Like oxalic acid, it
is employed chiefly for the purpose of precipitating lime
from its solutions (218) ; for this purpose, it may be dis-
solved in about six times ita weight of water.
Phosphale of Soda and Ammonia (Microcosmic Salt).
(NaO,NH.O,HO,POs+8Aq.)
715. This ealtoccasionallyeontainstrp^eaof chloride
=vGoo(^lc
242 REA CENTS.
of sodium, wJiieb may reaflilj' be detected by adding a
few drops of nitrate of silver to a solution of the salt,
acidified with nitric acid, when a eiirdy white precipitate
indicates the presence of the chloride (429).
Microcosmie salt is used almost exclusively in blow-
pipe experiments ; when heated, it is decomposed, the
ammonia and water are expelled, and soda, with excess
of phosphoric acid, ia left.
Potash {KO).
716. On account of its strong affinity for many sub-
stances, and its property of readily decomposing others,
caustic potash is rarely found free from impurities.
Those most commonly met with are organic matter,
sulphate and carbonate of potash, chloride of potassiiim,
silicic acid, and alumina.
(a) If organic matter is present, the solution of potash
is more or less brown, and, on evaporation, leaves a
brown residue.
(6) Sulphuric acid is detected by diluting the potash
with water, eupersaturatiug with nitric or hydrochloric
acid, and adding chloride of barium, when, if it is
present, the white insoluble sulphate is thrown down
(403).
(c) If carbonic acid is present, lime water causes a
white precipitate, which is soluble with eft'ervescence
when the solution is supersaturated with hydrochloric
acid (420).
{d) A little of the diluted solution is supersaturated
with nitric acid, and tested with nitrate of silver : a
white curdy precipitate, soluble in ammonia, indicates
chlorine or chloride of potassium (429).
(e) Neutralize a small portion with hydrochloric acid,
and evaporate to dryness: if the residue is not wholly
soluble in hydrochloric acid, silica is probably present
{/) If alumina is present, it will be precipitated when
the potash solution is neutralized with hydrochloric acid,
and treated with a alight excess of ammonia (241).
717. Potash is used chiefiy for the purpose of pre-
cipitating some of the metallic oxides from their saline
=vGoo(^lc
KEAGBNTS. 243
solutions, which it does on account of its strong affinity
for the aeida witli which they were in combination.
CuO,SO,-^KO,HO^KO,SO,+C\iO,RO.
It is employed also for neutralizing acid solutions,
decomposing organic compounds, and many other pur-
poses. A solution of potash having a specific gravity
of about 1060, is a convenient strength for moat analj'-
tical purposes.
Carhanate of Potash (K0,C0^+2Aq).
718. This salt generally contains traces of sulphate
and chloride, and occasionally silica and alumina.
{a) A solution, supersaturated with nitric acid, and
tested with chloride of barium, gives a white precipitate
if any sulphuric acid is present ^03).
{b) A solution similarly acidified, gives, with niti-ate
of silver, a white curdy precipitate, if it contains chloride
of potassium (429).
(c) Weuti'alize a portion of the solution with hydro-
chloric acid, and evaporate to dryness : if the residue does
not wholly dissolve when treated with hydrochloric
acid, silica is probably present (425).
id) If carbonate of ammonia causes, in a neutralized
solution, ft white gelatinous precipitate, alumina is pro-
bably present (243).
Carbonate of potash is frequently employed to pre-
cipitate metallic oxides and carbonates from their solu-
ble combinations, and for the purpose of neutralizing
acid solutions.
Nitrate of Potash (KO,NOj).
719. Nitrate of potash often contains traces of sul-
phate and chloride, and occasionally- nitrates of soda
and lime.
{a and 6) The sulphate and chloride may be detected
with chloride of barium and nitrate of silver (718, a
and 5).
(c) If lime is present, it causes a precipitate when the
solution is treated with oxalate of ammonia (218).
{d) The presence of nitrate of soda causes the salt to
deliquesce iti a moist atmosphere.
=vGoo(^lc
244 REAGENTS.
720. It is used almost eseiusively in the dry state, for
the pui-pose of oxidizing substances, wMch resist other
methods of oxidation; this property is owing to the
oxygen of the nitric acid being loosely combined, and
at a high temperature readily yielded up to any sub-
stance which has a strong affinity for it, such as sul-
phides, organic matters, &e.
Iodide of Potassium (KI).
721. Iodide of potassium is often adulterated with
carbonate of potash ; sulphate of potash and chloride
of potash are also often present. It should always be
in the form of well-defined (cubical) crystals, as the
adulterated varieties are readily distinguishable by their
imperfect crystalline form.
{a) Add a little dilute hydrochloric acid : if effer-
vescence takes place, some carbonate is present (419).
{b) If Bulphatea are present, they may be detected by
adding chloride of hariura, which will, in that case,
cause a white precipitate, insoluble in nitric acid (403).
(e) Add a little niti-ate of silver ; thia will cause a
pale yellow precipitate of iodide of silver, together with
chloride of silver, in ease any soluble chloride is pre-
sent. To separate them, filter the mixture, and after
washing the precipitate, treat it with a slight excess of
ammonia, which dissolves the chloride (if any), and
leaves the iodide undissolved (4S3) ; on neutralizing
the ammoniacal solution with nitric acid, the appear-
ance of a white curdy precipitate indicates the presence
of a chloride (429).
Iodide of potassium is employed chiefly as a test for
lead, mercury, and occasionally some of the other
metals. For use as a reagent, one part of the salt may
he dissolved in ten parts of water.
Chromale of Potash (KO.CrOj).
722. This salt occasionally contains traces of sulphate
of potash, which ia readily detected by precipitating a
little of the solution with nitrate of baryta, and adding
an excess of nitric acid, which redissolves the chromato
of baryta, while any sulphate remains inEohible.
=vGoo(^lc
REAGBXTS. 245
It is employed as a test for several of tlie metallic
oxides, with many of which it forms insoluble salts
(ehromates), of characteristic colors, as the cliromate of
lead (363), which is bright yellow. For use as a reagent
it may he dissolved in ten times its weight of water.
Vi/anide of Potas&iwm, (KOj).
723. Cyanide of potassium is sometimes used in
blowpipe experiments, and also as a liquid test. It
should be colorless, and entirely soluble in water.
Ferrocyanide of Fotasshim (Kj,FeCyg +3 Aq). (YcUoio
Priissiale of Potash.')
724. This salt, as met with in commerce, is suffi-
ciently pure for the pui-posea of testing. It is em-
ployed as a test for the perealts of iron, with which it
forms a deep blue precipitate of seaquiferrocyanide of
iron, or Prussian blue (282). It gives characteristic
precipitates, also, with some other metals. B'or use as
a reagent, one part of the salt may be dissolved in fif-
teen or twenty parts of water.
Fcrridcyanide of Potassium (K^jFOjCyg). {^Re<l Prussiate of
Potash.')
725. It occasionally contains traces of the yellow
prussiate, which is easily detected by tlie solution giv-
ing a blue precipitate with perchloride of iron (282). It
is used as a test for the protosalts of iron, with which
it forms a blue precipitate of fenidcyanide of iron (276),
which is similar in appearance to that formed by ferro-
cyanide of potassium with the persalts. It may be dis-
solved in ten or fifteen parts of water.
A7itimonia(e of Potash (K0,81)0i).
720. This substance seldom or never contains any
impurity that can interfere with its action as a test for
soda, which is the only use to which it is applied in the
laboratory. It must be kept in a well stoppered bottle,
and carefully excluded from the air, as the carbonic acid
is liable to decompose it, and cause a precipitation of
antimonic acid.
=vGoo(^lc
346 REAGBHTS.
Carbonate of Soda (NaO,CO, + 10Aq).
727. The beet method of preparing pure carbonate
of eoda, is to ignite the crystallized bicarbonate (iNaO,
H0,2C0j), when the second equivalent of carbonic acid
and the water are expelled, and pure anhydrous carbo-
nate is left. The salt of commerce frequently contains
a little sulphite and chloride, which may be detected
in the manner already detailed (718 a and b). The
more impure varieties contain also 'traces of sulphide of
sodium, and sulphite and hyposulphite of soda. These
may be detected by adding dilute snlphurie acid, and
passing the evolved gas into a solution of acetate of
lead ; this should cause a white precipitate of carbo-
nate of lead (422), and not a brown one (438); and no
precipitation of sulphur should take place on the addi-
tion of the acid.
728. It is employed for the same purposes as carbo-
nate of potash (718) ; also as a flux for the blowpipe,
and for iuaing with insoluble silicates, &c, For use as
a liquid reagent, one part of the salt may be dissolved
in ten parts of water.
Plw^hafe of Soda (2NaO,HO,PO,+24Aq).
729. This salt sometimes contains a little sulphate and
chloride. To detect these impurities, add to one por-
tion, in solution, chloride of barium, and to the other
nitrate of silver, and supersaturate both with nitric
acid : if the precipitate does not entirely dissolve in
either ease, a sulphate or chloride is present (403, 429).
It is employed chiefly as a test for magnesia, with
which it forms, in the presence of amraoniaca! salts, the
double phosphate of magnesia and ammonia (206).
For the purposes of testing, it may be dissolved in ten
parts of water.
Bm-ax {Biboraia of Soda), (NaO,2BOd-l Aq).
730. Boras occasionally contains traj^es of sulphate
and chloride, which may be detected in the same way
as in the phosphate of soda (729). It is employed
almost exclusively as a flux in blowpipe experiments,
=vGoo(^lc
RBAOBSTS. 247
foi' which pni'pose it ia admirably adapted; the second
equivalent of boracie acid which it contains, exerts a
strong affinity for bases at a high temperature, and is
eapaoie of displacing several aeids from their combina-
tions ; it also forms many double compounds and mix-
tures which are readily fusible.
Lime Water (CaO in WaUr).
731. This reagent is prepared by digesting hydrate
of lime (CaOjHO) in eold distilled water for an hour or
two, stirring the mixture occasionally, and when the
undissolved portion of the lime has subsided, pouring
off the clear solution, and filtering if necessary. As it
is liable to spoil when exposed to the air, owing to tlio
absorption of carbonic acid, it should be kept in a well-
stoppered bottle.
7S2. Lime water should be sufficiently strong to turn
the yellow color of turmeric instantly and decidedly
brown ; and, when tested with carbonate of soda, should
throw down a copious white precipitate of carbonate of
lime (214). It is used aa a teat for carbonic acid and
some of the organic acids ; for expelling ammonia from
its combinations, and for many other purposes.
Sulphate of Lime (CaO,S05+2Aq).
733. Sulphate of lime being xerj sparingly soluble
in water, is always used in the form of ^ saturated so-
lution, which is prepared by digesting the sulphate in
water, stirring it occasionally, and pouring off the clear
solution from the undissolved portion. It is used chiefly
as a test for some of the organic acids, and for dis-
tinguishing baryta from strontia. The solution ought
to give an immediate precipitate of sulphate of baryta,
when tested with chloride of barium (225).
Chloride of Cak-inm (CaCl).
734. This substance occasionally contains a little li-ee
acid, and traces of iron. The first is detected by test
paper, and the latter, if present, causes hydrosulphate
of ammonia to throw down in the solution a black pre-
=vGoo(^lc
cipitate, or to impart a greenish tint to the liquid (279).
As a reagent, chlorido of calcium is emplojed chiefly
in testing for some of the organic acids. It is also o±
great use in the laboratory as a drying a^ent, having so
strong an affinity for water, that a moist gas passed
over it, is rapidly and completely deprived of its water.
For this purpose the chloride need not be absolutely
pure : it shoifld not be fused, hut merely dried, as the
unfused is more porous, and consequently offers a larger
amount of surface to any gas passed over it.
Chloride of Barium (BaOI+2Aq).
735. Chloride of baiium sometimes contains traces
of iron and lime. It should not be discolored by hy-
droeulphate of ammonia (279), and, after being treated
with a slight excess of sulphuric acid, and filtered, the
clear solution should leave no fixed residue when evapo-
rated on platinum foil ; because the whole of tlio baryta
is separated by the sulphuric acid, and any other fixed
matter must be some impurity.
It is used chiefly for the purpose of testing for acids
(558), especially sulphuric, with which it forms the in-
soluble sulphate of baryta (403), For use, one part of
the salt may be dissolved in ten parts of water.
Mirate of Baryta (EaO.NOs).
736. titrate of baryta is liable to the same impurities
as chloride of barium (735), and they may be detected
in the same way. It should also be free from any
chloride, which may be known by adding nitrate of
silver (429). Its uses are the same as those of chloride
of banum, for which it is occasionally substituted in
eases when the addition of the chloride would interfere
with the subsequent stages of an analysis, as when we
have to test for chlorides in the same solution (605).
For use, it may be dissolved in ten parts of water.
Ferdilonde of Iron (Fe,01,).
737. This salt is liable to contain a little free acid,
and traces of the protoehlorido (FeCl). The free acid
=vGoo(^lc
is detected in the manner described in (535, b) ; and if
any protosalt of iron is present, the solution gives a blue
color with ferridcyanide of potassium (276). It is used
as a teat for some of the organic acids, and is also some-
times useful in the determination of phosphoric acid.
It may be dissolved in five parts of water.
Nitrate of C'oball (CoO,NO,-|-6Aq).
738. This reagent is used chiefly for the detection of
alumina, zinc, magnesia, and some other substances, by
means of the blowpipe (124). The solution employed
for this purpose may contam one part of the salt aia-
eolved in ten of ■water.
Sulphate of Copper (CuO,SO,+5Aq).
739. This salt is occasionallj^ usedasatest for arsenic
(311), and for otherpurpoeea ; it may be dissolved in ten
paits of water. The ammomo-sulphate of copper [OuO,
2]VHg,E0,S0^, which is also used in testing for arsenic,
ie prepared by adding ammonia to the solution of sul-
phate of copper, until the precipitate at first formed is
nearly all dissolved, when the solution is filtered, and
kept for use.
Ace/ctte o/Zcad (PbO,C:,H,03-f-3Aq).
740. Acetate of lead is used as a test for several .^cida,
which form with oxide of lead insoluble salts. For
testing, one part of the salt may be dissolved in ten
parts of water.
Sulacelato of Lead (SPbOiC^H^Oj).
741. The subaeetate is prepared by boiling together
equal weights of the neutral acetate (740) and protoxide
of lead (PbO) in water, and filtering the solution, which
must be kept in a well-stoppered bottle, as it is easily
decomposed when in contact with the air, owing to the
strong affinity of the oxide of lead for carbonic acid,
Both this and the neutral acetate arc used in testing for
hydrosulphurie acid, and for some of the other acids,
especially carbonic.
=vGoo(^lc
250 REAUENTK.
Nitrate of Silver (AgOjNO,).
742. This reagent is sometimes adulterated witli
nitrate of potash, and occasionally contains traces ot
copper and lead. When precipitated by a slight excess
of hydrochloric acid, the filtered solution ought to leave
no fixed residue when evaporated on platinum foil, as
the whole of the silver would be thrown down (377),
and any impurity would remain in solution. Copper
is detected by adding ammonia in excess to the solution,
when it will give the liquid ahlue tinge (369). Niti'ato
of silver is used chiefly as a test for chlorine {chlorides
and hydrochloric acid), and also for phosphoric and
some of the other acids. !Por use as a reagent, one part
of the salt may be dissolved in twenty parts of water.
743. The ammonio-nitrate of silver {AgO,'iNH'^,NOr^,
used as a test for arsenic, is prepared by adding
ammonia to a solution of the nitrate, until the precipi-
tate at first thrown down ie nearly all redissolved, and
filtering from the undissolved oxide.
Ferchloride of Mtrcary (ligClg).
744. This is occasionally employed as a test for hy-
driodic and some other acids, and also for some kinds
of organic matter: for this purpose it maybe dissolved
in twenty parts of water.
Protochloride of Tin (SnOl).
745. Protochloride of tin is prepared hy boiling
metallic tin in strong hydrochloric acid, care being
taken that a portion of the metal remains undissolved,
as otherwise a little perchloride might be formed; the
solution is then filtered, acidified with a few drops ot
hydrochloric acid, and diluted with about four times
its bulk of water. A few fragments of metallic tin
should be kept in the solution, in order to prevent the
foi-mation of any perchloride.
746. Protochloride of tin is employed chiefly as a test
for gold and mercury, and also as a deoxidizing agent,
for which purpose it is well adapted, on account of its
strong tendency to combine witli oxygen or chlorine.
=vGoo(^lc
REAGENTS. 251
It oceaaion ally contains traces of lead and iron, wbieh
may be detected by adding hjdrosulphate of ammonia
in excess to the solution, when, if pure, tbo precipitate
is wholly redissolved, but, if eitber of tbose metals is
present, a black residue is left, since their aulpbides are
insoluble in the hydrosulphate.
Perchhride of GoU (AuClj).
747. This reagent is used almost exclusively as a test
for the protosalts of tin (386), so that a very small
quantity iviH be found sufficient for the purpose of test-
ing. One pai't of the salt may be dissolved in thirty
parts of water.
Bichhrnh of Platinum (PtGl,).
748. Bichloride of platinum is employed only as a
test for potash, soda, and ammonia ; it may bo dis-
solved in about ten parts of alcohol.
Sulphate of Indigo.
749. This substance may be prepared in solution, by
dissolving a little indigo in strong sulphuric acid, and
diluting the acid solution with water, so as to form a
pale blue liquid. It is used chiefly as a test for nitric
acid and chlorine, by which it is' decomposed, and its
color discharged.
Solution, of Starch CO,^S^<,OJ.
750. This is made by gently boiling starch with
water. It is employed as a test for iodine, for which
purpose small pieces of tliread on paper may be steeped
in the solution, dried, and kept for use.
Slach Flux.
751. Black flux is an intimate mixture of carbonate
of potash and finely divided charcoal, and is prepared
by deflagrating in an iron spoon or crucible, a mixture
of two parts of bitartrate of potash and one of nitre.
It is used as a reducing ilux in blowpipe expeiiraents.
=vGoo(^lc
Distilled Water (HO).
752. Pure distilled water is prepared by oarefnlly
dlstilliug any of the common Mads of water either in
a still or retort, rejecting the firat and last portions (62).
For many pui-poses, rain water, when collected at a
distance from towns or manufactories, and boiled and
filtered, will be found sufficiently pure ; but in analy-
tical experiments, distilled water ought always to bo
iised,
758. Before taking it into use, it should ho tested
with the following reagents : —
(a) Litmus ana turmeric paper, for free acids and
alkalies.
(J) Chloride of barium for sulphates (403).
(e) Nitrate of silver for chlorides (429). The mixture
shortly becomes dark-colored, especially if organic
matter is present,
(d) Oxalate of ammonia for lime (218).
[e] Lime water for carbonic acid (420).
(/) Hydrosulphate of ammonia for any metals of the
third or fourth class.
(^) When heated on platinum foil, it should leave no
trace of solid residue.
Distilled water is used chiefly as a solvent, and for
washing precipitates,, besides many other purposes to
which it is constantly applied.
Alcohol (C\H^,0,EO).
754. The alcohol commonly used in chemical expe-
riments should have a specific gravity of about 0'83,
except in cases where absolute alcohol is required, when
it should be 0-796. Wlien evaporated on platinum foil,
it should leave no residue, and should not change the
color of litmus paper. It is used chiefly as a solvent,
i for the purpose of facilitating the precipitation of
--"■ a which are less soluble m it than in water.
=vGoo(^lc
WEIGHTS AND MEASURES.
Tivi/ or Apothecaries' WeigM.
Oiinoea. BracbmB. Soraplea, Grains.
12 = as = 288 = 5760
1 = 3 = 60
1
=
0-064
Aeoirdvpois WeigJd.
25G = VOOO
Ifi = 437-5
1 = 27-:-i43
F
ench Gram
453-25
28-328
1-77
Imperial MeasuTe.
rluid Ounces. Fluid Bracinis
= 160 = 1280
= 20 = IGO
=
Minims.
70,800
0,000
WdgM of Waiei- at 62°, contained in the Imperial Gallon, &c.
Orniiis.
1 Imperial Gallon
=vGoo(^lc
APPENDIX,
C'libic Incites coniained in the Imperial Gallon, &c.
Gallon
=
. 2T7'273
Pint
34-659
Fluid Ounce
vni
Fluid Drachm
0-21GG
Minim
=
0'0036
FRENCH WEIGHTS AND MEASURES.
Measures of Lengtli.
Millimetre
=
■[i3h:-it
Centimetre
■39371
Decimetre
3-93710
Metre
39-37100 Mii. r
Decametre
393-71000 =
Hecato metre
3937-10000 =
Kilometre
39371-00000 =
Mjriometre
303710'00000 = G
Measures of Capacity
MiUiliti'e
■06103 =
Centilitre
■61028 =
Decilitre
6-10280 =
LitJre
6r02800 =
Decalitre
610-28000 = 2
Hecatolitre
6102-80000 = 22
Kilolitre
61028-00000 = 220
Myrlolitre
G10280'00000 = 2200
Measv-rea of Weight
English Grains.
Milligramme
■0154
Centfgramme
=
■1544
Decigramme
1-5444
Gramme
15-4440 Poun
Decagramme
=
154-4402 =
1554-4023 =
Kilogramme
15444-0234 = 2
Myriogramme
=
I54440'2344 = 22
siGooi^le
APPENDIX.
Showing Hie QuaiitUy of OH of Viti-wl (30,80^) of sp. gi: 1-8485,
and of Anhydrous Acid (SOj), in 100 Parfn of dilute Sulphuric Acid,
of different Specific Gravities (K'e).
LiiiuW
Sp. Gr,
Drj- A^id.
IS'l'
Bp. I3r. j Dryicid. '.
100
1-8485
81-64
65
1-5390
53-00
99
I-847S
88-73
64
1-5280
62-lS
98
1'8460
79-90
03
1-5170
51-87
97
1'8439
79-09
1-5060
50.55
66
1-8410
78-38
61
1-4960
49-74
95
77-46
60
1-4860
48-92
94
70-06
59
1-47G0
48-n
1-8290
75 -sa
68
1-4060
47-29
92
1-823S
76-02
67
1-4560
46-48
91
1-8179
74-20
56
1-4460
45-66
90
1-Sil5
78-89
55
44-85
89
18043
72 57
64
1-4266
44-03
88
1-7962
71-75
63
1-4170
43-22
87
1-7870
70-04
52-
1-4078
42-40
1'7774
70-12
61
1-8977
41-58
85
V7673
69-31
60
1-3884
40-77
8d
1-7570
40
1-3788
39-95
S3
1-7465
67-68 .
48
1-8697
89-15
82
1T860
66-86
47
l-36t2
3S-82
81
17245
6605
46
37-51
SO
1-7120
66-28
45
1-3440
36-69
79
16993
61-42
44
1-8845
35-88
78
16870
63-60
43
1-8255
86 06
77
1-0750
62-78
42
1-3165
34-25
76
16630
61-97
41
1-S080
83-43
75
16520
61-15
40
12999
32-61
74
1-6415
60-34
39
1-2918
81-80
73
1-6821
59-82
88
1-2S20
30-98
72
1-6204
58-71
87
1-2740
30-17
71
1-6090
57-89
1-2654
29 as
70
1-5975
57-08
35
1-2572
2864
1-5868
56-26
84
1-2490
27-72
08
16760
55-45
33
1-2400
26 91
67
15048
54-63
32
1-2S34
2609
66
1-5503
63-82
31
1-2260
25-82
siGooi^le
TABLE 1. — Uontimied.
UqrfiS.
......
»""'■
Liq,.:ii ap. Or.
Bry Ai^id.
SO
1-2184
24-46
15 1
1019
12-28
29
1-2108
28 -66
14 ]
0953
11-41
22-88
13 ]
0887
10 60
27
M956
22-01
12 ]
3809
9-TS
26
1-1876
21-20
11 I
0748
8-97
25
1-1792
20-38
10 1
0682
8-15
1-1706
19-S7
9 1
0614
7-34
].I62S
18-75
>644
0-52
22
1-1549
17-94
7 1
D477
5-71
21
1-1480
17-12
6 1
M05
4-89
1-1410
16-81
6 1
4-08
19
1-1830
15-49
4 1
)268
3-20
18
M348
14-63
3 1
>206
2-446
17
1-1165
18 84
2 1
)140
1-6-^
IG
1-lOUO
13-05
1 1
0074
0-8154
SJwwing the Qimniiiy of Becd or Aniiydrous Nitiie Acid (TSOf) in 100
Farts of Liquid Acid, of diffwent Speeific Gravities ( Ure).
Heal ada
Sen Biiid
Ee»] add
Speciflo
Bpedfle
''^Liquia. "
Gm^it,.
Liquid,
Liquid. '
1-5000
79-700
1-4600
68-542
1 1-4065
67-384
1-4080
78 903
1-4570
67-746
1-4023
66-587
1-4D60
78-106
1-4530
66-948
1-8978
56-790
1-4940
77-309
1-4500
66-155
1-3945
54 003
14910
76-512
1-4460
66-854
1 -8882
64196
1-4880
75-715
1-4424
64 557
53-399
1-4850
74-918
1-4385
63-760
18783
1-4820
74-121
1-4346
62-963
1-8732
1-4790
73-324
1 -4-506
62-166
1-3681
61-068
I -4700
72-527
1-4269
61-369
1-8680
50 211
1-4730
71-730
1-4328
60-572
1-3579
494i4
1-4700
1-4189
69-775
1-8529
48-617
1-4670
70-186
1-4147
58-078
1-3477
47-820
1-4640
69-339
1-4107
58-181
1-3427
47-023
siGooi^le
APrBNDIX,
TABLE U.~OjHli,tncd.
Beal acid
Ileal acid
Kcal »<.:d
SpMi6=
Spedfla
Sp«^Ho
OtsYity.
parts of thu
Gra^ily.
parts of the
Gravity.
Liquid.
Liquid.
Liquid.
1'3876
46 226
1-2212
30-286
1-1051
15-143
1S323
45-429
1-2148
29-489
1 0993
14-346
1-8270
41-632
1-2084
28692
1-0935
13 649
1-3216
43-835
1-2019
27 '895
1-0878
12-752
1-3163
43-038
1-1958
27-098
1-0821
11 -955
1-3110
42-241
1-1805
26-801
1-0764
1M68
1-8056
41-444
1-1833
25-504
10708
10-361
1-3001
40-6i7
M770
24-707
1-0651
9-564
1-294T
39-850
1 1709
28-910
10595
8-767
1-2887
89-053
1-1648
23-113
10540
7-970
38-256
1-1587
22-316
1-0485
7-173
1-2765
87-459
21-619
10430
3-376
1-2705
36-662
1-1465
20-722
10375
5-579
1-26M
35-865
1-1403
19-925
1-0320
4-782
1-2688
35-068
8 936
1-2523
34-271
1-1286
18831
1-0212
3-188
1-2*462
33-474
1-1227
17-534
1-0159
2-391
1'2402
32-677
11168
16-737
1-0106
1-594
1-2341
31-880
M109
ID -940
1-0053
0-797
1-2377
31-083
ShmBtng the Quaniilji of Anlnjdiims JlydrocJilorio Add (HOI) v,
Liguid Acid of different Specific Gravities [Ure),
in 100
Speelfio
o.„...
as
Ous.
.tfl
SpfdEo
Qr»Tity.
0„.-..
ir
89 675
40-777
9*^
1-I857
36-603
87-516
99
1-1982
89-278
40-369
91
M846
36-107
37-108
9H
1-1964
38-882
39-961
90
M822
85-707
86-700
H7
1-1946
38-485
39-554
11802
35-310
86-292
96
1-1928
38-089
39-146
1-1782
34-913
S5-884
Mfi
1-1910
87-692
88-738
M7
34-617
86-476
94
M893
37-296
38-880
86
1-1741
34-121
35-068
y3
1-1875
30-900
37 923
1-1721
33-724
34-660
siGooi^le
APPENDIX.
TABLE ill.— Continued.
a
Specific
0„„.
»
Arid
Speaifle
„„„,...
nya™- 1
Si
1-1701
83-828
84-252
42
1-0838
16-664
17-126
1-1681
82-631
33-845
4L
10818
16-267
16-718
83
M661
82-535
33-437
40
1-0798
15-870
16-310
8i
1-1641
32-136
88-029
89
1-0778
16-474
15-903
1-1620
31-743
32-621
1-0758
16-077
15-494
79
1-1599
81-843
32-213
1-0738
14-680
15-087
78
1-1878
30-946
31 -80.5
36
10718
14-284
14-070
77
1-1557
30-550
31-398
36
1-0697
13-887
14-271
T6
1-1536
80-158
80-900
34
1-0677
13-490
18-863
75
1-1615
29-757
30 582
1-0657
18-094
13-456
74
1-1494
29-361
80-174
82
1-0687
12-507
13-049
T3
I -1173
28-964
29-767
81
1-0617
12-300
12-641
72
1-1452
28-567
29-359
30
1-0597
11-903
12-233
71
1-1481
28-171
28-951
29
10577
11-506
11-825
70
1-1410
27-772
28 544
28
1-0667
11-109
11-418
09
1-1389
27-876
28-136
27
1-0537
10712
11-010
68
26-979
27-723
26
1-0517
10-816
10.602
6-
1-1349
26-683
27-821
26
1-0497
9-919
I0'19i
66
26-186
26-913
34
1-0477
9-522
9-788
m
1-1308
25-789
26-505
1-0457
9-126
9-879
64
1-1287
26-098
22
1-0487
8-729
8-971
68
1-1267
24-996
25-690
21
1-0417
8-832
8-563
M247
24-599
20
1-0397
7-985
8-165
'61
1-1226
24-202
24-874
19
1-0377
7 -538
7-747
60
1-1206
23-805
24-466
18
1-0357
7-141
7-340
59
1-1185
28-408
24-058
17
1-0387
6-745
68
1-1164
28-650
16
1-0318
6-348
6-524
57
1-1143
22-616
23-242
15
1-0298
6-951
6-116
6Q
11128
22-318
22-834
14
1-0279
5-554
5-709
56
1-1102
22-426
18-
1-0260
6-158
5-301
64
1-1083
21-425
22-019
12
1-0239
4-762
4-893
58
1-1061
21-028
21-611
11
1-0220
4-486
62
1-1041
20-682
21-203
10
1-0200
4 078
51
M020
20-235
20-796
9
1-0180
8-671
3 670
50
11000
19-837
20-888
8
1-0160
8-174
8-262
49
10980
19-440
19-980
7
1-0140
2-778
2-854
48
1-0960
19 044
19-572
C
1-0120
2-381
2-447
47
10939
18-647
19-165
i-ono
1-984
2-039
46
1-09I9
18-350
18-767
4
1-ooeo
I -631
46
17-854
18-849
3
1-0060
1-191
1-224
44
10879
17-427
17-94!
2
1-0040
0-795
081B
43
1-0859
17-060
17-584
1
1-0020
0-397
0-408
siGooi^le
APPENDIX.
Showing the Qiuinlily nfAnhydiou^ I
dijfnent Spi.cifir Grani
lil, {KO) h
t {Dalloi)
Potash
aieciR.-
P01.-1
per cent
Gravity
percent
512
}2q"
1 88
26 3
221°
1-60
46 7
200
23 4
L24
1-52
421
276
123
It 5
220
1-47
33 6
2b5
111
362
^\-i
1-44
36 8
255
1 1'-
13
-I-;
1'42
8*4
216
I 11
)5
214
1-89
a2 1
240
10b
17
213
1'3G
2U
^"4
Showing the Quantity of Anhi/drovs Soda (NaO) i
diffbreni Spteifie Gravities [Dalton].
j,„.,.
£od«
iwitag-
Or.vity.
per coot.
— =?
1-40
29-0
242°
600
260
286
1'72
68-8
400
1-32
22'0
228
46'6
800
1-29
10-0
224
166
41-2
280
1-23
16'0
220
1-60
36-8
1-18
ISO
217
255
1-12
9-8
214
. 1-44
310
248
1'06
4-7
213
siGooi^le
APPENDIX.
SkowinQ ilte Quantity of Artimoniacal Gas (KHj) in Aqiieoiis Solutio;
of different Specific Qravilies {Balton).
SpecilJC
Gravity.
"•'Zt^r'
BoilinE-
pollitt.
Ois liquid.
■850
35 3
26°
494
800
38
^50
J70
29^9
50
419
27'3
62
382
530
24 7
74
346
900
22^2
80
311
910
198
98
277
17^4
110
244
930
161
2H
940
12'8
134
180
950
105
146
147
960
158
116
970
173
87
4-4
187
5S
■990
2'0
190
28
TABLE \'1L
Shotiiing the Qaantity of Absnluie Alcoliol {C,HiO,HU) contained i
Diluted AlcoJtol of different Speeifio Gi'aviiies {Fownes).
l«
^ -
1=1
&.
^ll
5S|
o,
09991
05
0.9841
10
0-9716
20
0^9981
1
11
0-9704
09965
2
09815
12
0-9691
22
09802
0-9678
23
14
0-9665
24
09914
5
0-0778
15
09652
25
0-9706
0-96S8
9884
0753
17
27
9869
8
9741
18
0-9609
28
098&5
9728
19
09593
29
siGooi^le
APPENDIX.
TABLE Yil.—GonUaucd.
hi
lis
Sp, Gr, Bt Ooo.
u%
sil
lU
£=-!
1
g°-<l
p"
9578
30
9090
54
8533
78
8j60
81
9069
55
8608
79
95*4
32
9047
56
8483
80
9528
13
Od025
57
8459
81
9511
84
9001
58
0-8484
9400
OH970
69
0-8408
94
8956
60
84
945"
37
8932
61
0-8357
t5
9434
88
8908
62
8831
86
0416
89
63
8305
87
939(1
40
64
8279
88
93 e
41
8840
66
0'8254
80
9556
4"
8S16
66
08228
90
ODSgo
4^
8793
67
8199
91
9S14
44
(8769
68
08172
9 9^
45
8746
69
0-8145
9'
46
87151
70
8118
04
0J249
4-
8696
71
95
9''28
48
8672
72
0-8061
49
8649
73
8031
97
9184
50
8625
74
8001
OlbO
51
75
0-7969
9135
B
otsai
76
100
11
5
O'iJST
77
siGooi^le
SJtomng the Sjmrfto Gravities ofmixliircs ofE/Jier and Alcolwl I'j
different proportions {Dallon).
Gravity.
m^.r.
AlMbol
(sp.gr. 830),
Specific
«...
Alcohol
(Hp. KF. 830).
724
100
792
40
60
782
1)0
10
30
70
744
816
20
80
756
70
30
S28
10
SO
7G8
60
40
830
100
7S0
SO
SO
siGooi^le
APPKNDIX.
a}
i!
;„.,„
] ] „ „„, „
■3]ias¥
„™.,
_„J„J„ i.„....JJ U
■,„,
„ ,J„ !._..„„ ■.„i^„„„.„
■ail^K
,„!!:„.. 0_-„ : ^ i J. '■■'■
~,o
„„-..J.. „::.;.-.-■
,„.
Ei].,,_-J]„-„J-— ] '■.
,,™
■aiioiqo
„ „j2„,j;':
■.mr«
„.„„ ;;„„;J
■ounqd
■oipOHpfH
HJiqaoipfa
^^^^^^-^««-«„«H2cir,ri«»M««
■opisBJT
^ :
rtwr,«««=i=. ; ; :m :«M«=ifl««« : ; ;
■OPTEIS
■o,no,«3
^^^«=.«^ ;««=.« .c.« .««««« : ;«
„_,.„..»,.„„. :„„..„. :.
1
^ HJiqaoipfa
I
i
IP
II
!
!
1
siGoogle
APPENDIX.
i
till
If
!F
i
i!
.
5%
2-1-L
i§i
1
Nl
SIIS^l
Q
ia|
1
a
i%'
ili°
.SS.E •
.
f
i
llj«*
i
3
i
¥
a
g
•^
S
5
a
m
ill
°
u
^ f
1
j\i
&
ti
11
11
^
s
l*i|t
111
if!
i
i
^
H>it
li!
m
o
Hi!
s
ipTittii
^^
«lifip
°
1"
°
H
1
€
='
a
o"
1
H
•
iC
li
i:it
e!*
lilt
*'
siGooi^le
APPENDIX.
Slii
fill
1" = = S
is
lip'
III
if
Is
HI
ill
v5
PS'
1
i
=
o
ii
111
III
o
=>
ii
°
ll
■iliti
it sH
m
1^
^.2
|l
g-S
=
lii
=liil
Iflis
III"
Ii
||
u
1
till
Ms-
iili
n
|l
ill
lit
1
Ifii!
o
«!
=
s
1
1
°
IMI
ii
°
= =
1
=
1
i
1
1
S
i
j
1
is
53
1*
ills nk
iii' 111--
fJli
6U'
3
'I
siGooi^le
1
1
w
111
f!
'1
II
mm
lit
ill
1
1
11
1
1
n
|5
m
iiii
j}|j
1
1
=
1
it
lilt!
ll
i0i
°
ii
iji
iiil
1^
=
Hit
i^
9
1^
fl
=1
i^ili
ill
#1
|1
ii
111
tip
Is
1
1
5
1
IMS
II
=
111
1
1
1
i
o"
^
s
s
1
J«
ft ll
siGooi^le
tmn.
m
mi
i i"
Si
1
II
n
^1
i^ii III
ii
1
i
1
iiilil
\4
i
1
iit
8||
ii
f!
i 1
w
|i
ill
1
ji
lii
ll
=
J. i II
1
ft*
1
|j
lii
i
ii
i
ii
si
11
•s
= [ |l
Si?
li!
»
i
1
1
i
Ill
i
Us
!ii!
iia
Pi
siGooi^le
1
ill
illl
Hip
IfUfi
III"
lilt
Mi
til
■s-al
1 !
ttpiis
i
1
1
1
1
1
1
1
m
=
°
=
°
^1
s
It
Ijl
11^
3
=
to
ih
It
p
■_|i
1
° w
lll
.1
t
1
°
jii
l1
1?
sllal
«
pi
i1
111
II
lii
°
ll
i
iiiii
Jill
1
illl
=
lit
1
I
S
^
1
1
ii
r
§•5
II
f
si
If
sis:
siGooi^le
APPENDIX.
liiir
1
ffilij
1
U
»
1
i
ill
|l||it
o
o
s
i
ii
1
°
o
ii
1^
Ii
1
o
°
|i i^
il
Is
=
g.3
1 Ifl
h
ili
11
o
°
H \h 1
iPftl
=
=
Is
1
4
=
1
1
1
1
b"
+s
4f
3|
Is
Ii
siGooi^le
AT PEN!) IX.
1
11
1
ii
Id
s
1
mi
lllft
III
t
«|
m
1
1
llllfe
i
s
3
ll
1
J
ti
1
i
It
ft
^1
II
a
1
P
e"-gs|"
i
s
j.ll
!
M
i
hit
fi
li
111
i
1
iHh
1
1
1
iJllJ
1
Ifl'ti
°
=
i
1
4
g
^
4
■^
1
ii
5
1
J
siGooi^le
APPENDIX.
li.
it
m
1?
l|lt
ill
1
it
!
1
IK!
I'll
114"
Is =
iljii.
ilfll
II nil
iS|!i
ill"
II
il!
1
is
=
S||5
ii
mi
1
1; =
1
t
s
1
1
Ij
-»
is
It
1
j
2
3
i
1
°
!
'
i
1
I
1
s
11
1"
h
1
illll
sip!
liiii
Hlli
o
1
if
J
1
i
1
1
1*
||!
J
il
il
e
siGooi^le
i-'i
a
a
n
i
H
ti'ff.
ii
1
n
^'
1
turn
i
a
jlpi
i
111
S|
Bl
11
S4
1!
i
II
6~
"fs
J
III
ll
= S
«s
lit!
o
B
11
r
Is
i
31
lis
lit
■
-s
ffil
1
1
i
£
i
£
°
Sw
1
l!tt
1
°
1
o
°
!§?
a
i
1
^
^V.'
2|
II a^
Is
l!i
o
°
^
i
§'
4
s'
s
^
*
1
j
.
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APPENDIX
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APPENDIX.
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Barjta.
Stroiitia.
Lime.
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Baiyta,
Strontia,
Lime.
m combina-
tion with
phosphoric,
boraeic,
oxalic, and
some other
acids.
Magnesia
m combina
tion with
phosphoric
J
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Silver . . .
Lead . . .
Bismuth .
Copper . .
Cadmium.
Osmium .
I Yellow.
!■ Black.
Antimony
Arsenic .
Tin ... .
Gold . . .
Plaiinum
Iridium .
Mohjbdenui
siGooi^le
LIST OP SALTS, ETC.
WITTOn HAY BE EXAt
JIKED FOa fBACnCE IN QUALITATIFE
AHA
tY«.3 (Part III).
( )
alts, &ii., soluUe in Water.
Chloride b m
Protonitrate of mercury.
Sulphat J
PerohJoride of mercury.
Mufiate
Acetate of lead.
Sulphat n a
Sulphate of copper.
Chloride m
Nitrate of silver.
Nitrate ti
Sulphat h m m
Iodide of potaasium.
Sulphat
Biborateofsoda.
Sulphate m g
Nitrate of potash.
Chlorate of potash.
Protosulphate ot iron.
Pei-chlondeofii-on.
Carbonate of soda.
Sulphate of nickel.
Araenious aeid.
Nitrate of cotialt.
(6.) Simple SaUs, ^c,
insoluble in Water, hut sohbje in Acidi
Carbonate of magnesia.
Protoxide of lead.
Phosphate of lime.
Sulphide of antimony.
Carbonate of baryta.
Black oxide of copper.
Metallic zino.
Carbonate of etroatia.
Oxide of bismuth.
Snlphide ofii-oii.
Metallic tin,
(c.) Simple Sails,
^c, insoluble in Waier and Acids.
Sulphate of barjta.
Silica,
Sulphate of strontia.
Chloride of silver.
Chloride of lead.
Silicate of lime.
Sulphate of lead.
Silicate of alumina.
siGooi^le
(?) ¥ I '^11 l)-c., soluble in Water.
{ Chloride of V m
\ Nitrate of p tash
(Sulphate f
t Chloride of d
( Muriate of amm
( Phosphisl t od
iSnlphate t pp
Nitrate of b 1
SPerehloride of iron,
Sulphate of magnesia.
Alum (double STilphate of alumina
aud potash).
f Chlorido of calcium,
i Nitoate of potash,
I Muriate "
( Sulphate of uictel,
] Chloride of sodiuiu,
/ S Ipl to t magneaic
I Chi t f potash,
JBI t fsoda,
1 M k f mmonia,
f Nitrate of lead,
i Nitrate of cobalt,
t Nitrate of atrontia.
I Ntr ti
I Nt t f
Nt-at fl ad',
1 Is -at f opper.
S Ipli t fpotaMl),
1 h ph f Boda,
Bl t fsoda.
-Job t f
Chloride of potB
! Iodide of potasa
i^Niti'ate of i
(e.) Mixed Sails, ^c, imohible in Water, but soluble m Acids,
{Carbonate of magnesia.
Sulphide of ii-on.
( Protoxide of lea^il,
\ Phosphate of hme.
(Carbonate of lime,
Black oxide of coppei'.
f Oxide of bismuth,
i Sulphide of iron,
(Sulphide of antimony.
Magnesian limestone.
Iron pyrites.
Copper pyrites.
Argon tilerous galena.
German silver.
Avsenical cobalt ore.
The solid matter contained in
aea, well, or river water.
The portion of soils which is
soluble in acids.
(/ ) Mixed Salts, t^c., insoluble in Wafer and Acids.
i Chloride of silver,
Sulphate of baryta.
[Sulphate of lead,
-j Silicafe of alumina,
(chloride of diver.
=vGoo(^lc
GLOSSARY OF CHEMICAL TERMS.'
Absorption, fcoiii dbsorheo, to auck up ; the act of imbibing a liquid.
Acetic acid, from acettim, vinegar ; the acid coulaitied in vinegar.
Aeriform, from a^, the aiv, and forma, a form; haying the form or
properties of air.
Afpikitt, from, ad, to, and Jink, a boandary ; relationship ; the force
which canses particles of dissimilar Muds of matter to combine
together, so as to form new matter.
Albdmen, -iHooa, from albumeit, the ■white of an egg; au important
animal principle. The white of an egg consists chiefly of albumen
and water, contained in a celliikr tissue.
Ai:C0HOL, from an Arai>ic word j the intoxicating principle of spirituous
liquors.
Ai.CALi, ft soluble body, will a hot eauBtie taste, which possesses the
power of destroying or neutralizing acidity. Tlie term is derived from
the Arabic avticle, al, and ktdi, the Arabic name of a plant, from the
ashes ofwhieh one of the most important nikalies (potash) is obtained.
Amalgam, from "jia, together, and ytiiia, to marry; atermsignifjinglthe
union of any metal with mercury, which has the property of dissolving
several of the metals.
Amorphous, from d, not, and iisp<p>i, a form ; not possessing any regular
Akalooue, that which Is the counterpart of another.
Akalooy,-i<!AI,, and -ous, from dnh, among, and Xiiyo;, a relation or pro-
portion ; a likeness or resemblance between things, with regard to
their circumstances or effects.
Akalysis, from dnii, among, and \ta, to loosen; the separation of a sub-
stance into its component parts.
Angle, from anffidus, a corner; the inclination of two straight lines
to each other, which meet together, but are not in the same straight
AsHYBROus, from i, not, and ijtjp, water ; containing no water.
AuTlSBPTic, from dtri, against, and frSra, to putrely ; possessing the
power of preventing or retarding putrefaction..
AiJUA BbsiAj i. e., Begal Water, a mixture of niti'ie and hydrochloric
acids ; so called from its property of djsaolving gold, which was held
by the alchembta to be the king of the metals.
siGooi^le
280 AVPKNDIX.
Aqueo, from aqiw,, water ; when prefixed to a word, denotes that water
eaters into tiie composition of Ae substance which it signifies, as
ctgueo-sidphunc acid (HO,SO ),
ATHERMiNOTiS, from d, not, and Blppoi, heat; that through which heat
will not poHS, is said to be aOi&manaus.
Atmosphbrb, from dr/iSt, Taper, and o^atpa, a sphere: coramonly used
to denote the sphere of air which snrroafids the globe,
AtoMj-i"! from d, not, and rtjivoi, to cut ; a minute particle of matter,
not susceptible of iiirthar divieion.
ATTBiCTroH,-iTE, from od, to, and irahOj to draw; the tendency which
bodies have to approach or unite with each otlier.
Azote, from i, not, and !ufl. life ; another uame for nitrogen ; so called
because it ia incapable of supporting respiration.
Baricm, from y5ap*s, heavy ; the metallic base of barjta.
Baroubtbb, from iJii/mt, weight, and ifitpoi', a measure ; an instrumeat
for measuring the varjing pressure of the atmosphere.
Bakyta, a compound of oxygen and the metal banum (BaO), possess-
ing alfialiue properdes.
BiBDLOUS, Irom biho, to drink ; that which has the property of drinking
in, or absorbing, moisture.
BouON, a dark, olive-colored elementary substance, obtained from
boraoic acid, insoluble in water, and a non-conductor of electricity.
Bbominb, firom Bp^^fs, a strong odor ; an elementary liquid of a reddish-
brown color and aaffocating smell ; in chemical properties, it strongly
"is iodine.
Caloric, from ca^oc, heat; an imaginary fluid substance, supposed to
be diffused through all kinds of matter, and the sensible effect of
which ia called heat.
CAPiLLABy, from eapilhia, a hair, resembling, or having the form of
Capsule, from capsida, a little chest ; a small shallow cup.
Carbon, from carbo, a coal; the chemical name for charcoal.
Caustic, from irolu, to bum ; possessing the power of burxiing.
CB:BiiiSTRr,-iCAL, ftom an Arabic word, signifying the knowledge uf
the substance or constitution of bodies ; the science whose object is
to examine the constitution of bodies.
CuLORiHB, from ^Xw^it, green ; a greenish-colored gas,, of a pungent suf-
focating smell, and possessing chemical properties nearly allied to
those of oxygen.
Clbavaob, Plakb OF, the plana in which crystals have a tendency to
separate.
Cohesion, from cojj, together, and lusreo, to stick; the power which
causes the particles of a body, to cling together and resist separa-
CoHBUsrlOfT, from combltro, to burn ; the disengagement of light and
heat, which frequently accompanies chemical combination.
CowDUCTiON, from con, togetlier, and dum, to lead ; the power of trans-
mitting heat or electricity, without change in the relative position of
the particles of the conducting body.
=vGoo(^lc
APPENBIX. 281
CosGELATioh", from con, togethei", and gelo, to freeze ; tlie process of
freezing.
CoNSTirnENT, from conaUtuo, to put together; that of which anything
consiats, or is made up.
CoNTBAOTtOK, from Con, together, and tra7io,io draw; the state of being
drawn into a narrow compass, or becoming smaller.
Convex, fl.-om eon, together, and vefto, to cany ; curved outwardly, or
protnlierant.
CoKPDSCULAR, fi-Mni coj^ws, a body i composed of, or relating to, atoms.
CnysTALLOGitAPHT, from (r/KioroAAoj, a crystal or ice, and jfa^a, to Oe-
aoribe ; the science which treats of crystals.
CsYSTALiiZATiON ; tie formation of crystals during the passage of cer-
tain substances from a fluid to a solid state.
CuBB,-ic i a solid figure contained by six equal squares.
Cyanogen, from. Kiasot, blue, and ia></io}, to produce ; a eolorleea gas
composed of carbon and uitvogeu (C^N), Its chemical properties
much resemble those of oxygen and chlorine ; it derives its name
" 'ts entering into the composition of Prus'
cyanide of potassium (KjCjN).
with a metal is called cyanide, a
Decomposition i the resolution of a eoiupound substance into ita com-
ponent parts.
Decrepitation, from de, from, and crepiio, lo cracide ; the crackling
noise which certain salts make when heated, usually caused by the
sudden escape of water.
Deflagbation, from defiagro, to burn ; burning.
Dbliquescencb, from deliqueo, to melt ; a gradual melting or dissolving,
caused by the ahaorption of water from the atmosphere.
Density, ftom deiwus, thick ; vicinitj or closeness of particles; specific
weight.
Deoxihizb ; to deprive of oxygen.
Detonation, from detono, to thunder ; explosion accompanied with
DiAFHAKoua, from W, through, and *m'™, to sHne; that which allows
a passage through to the rays of light, but disperses them so as to
prevent direct vision.
DiATHERHAKOua, from iid, through, and fl£f>(iiir,heat ; that through, which
heat will pass, is said to be dxatlier'nwMous.
D1M6BPHOTI8, from ilfT twice, and /»p*ii, a form; having two distinct
crystalline forms.
DiaiNTEGKATioN, from dis, meaning sepai-ation, and integei; whole ; a
complete separation of particles.
Distillation, a separation drop by drop ; the process by which a fiuid
is separated from another substance by first being converted into
vapor, and afterwards condensed drop by drop.
DoiiECAHBBBON, (rom luSua, twelve, and Ufa, a ba.'je or side; a solid
figure contained by twelve equal sides,
EncLLiTiON, from ehrUHo, to boil ; the act of boiling.
=vGoo(^lc
282 APPENDIX.
Eppebtescence ; the escape of bubbles of gas formed in a liquid, as
when marble ia decomposed by hydrochloric acid.
Epplorescesce, from, effiuresca, to blow aa a flower; the formation of
email otystala on tte surfaces of bodies, in consequence of the
abstraction of water from, them by the atmoaphere.
EiJ)CTRioiTT, from BXctrpot, amber ; the name of a power of matter,
which produces a variety of peculiar phenomena, the first of which
were ODServed in the mineral snbstance called ambei- ; the laws,
hypotheses, and experiments by which they are espliuned and illus-
trated eonatitute the science of electricity.
Electkode, from BAht/mv, electricity, and Mi;, a way; the point at
which an electric current enters or quits the body through which it
passes.
Electrolysis, -ltte, from i\utpov, electricity, and i6u) to loosen; the
into two or more parts, and contains but one feind of ponderable
matter.
BMPYBBUM4T1C, trom iir, in, and "*C, fire ; having the taste or smell of
burnt animal or vegetable substances.
Esdosmose, from Man, within, and lio-pj;, the act of pushing ; a flowing
from the outside to the inside.
Eqciyalent, from ceqiius, equal, and valeo, to be worth ; equal in value,
or in the power of combining with other substances.
EvAPORATioH, from a, Dut, and jiapor, vapor ; the conversion of a liquid
into vapor.
EsosMOSE, from Efoi, without, and uwyiSf, the act of pushing ; a flowing
from the inside to the outside.
EspAWSiOM, from expando, to open out; the enlargement or increase in
the bulk of bodies, which is produced by heat.
EsPERiMEiTTi from es^erioTfia attempt, to try; something done in order
to discover an uncertain or unknown effect.
ExPLOSios, from sc, out,andj>taMiJo,to utter a sound; a sudden expan-
sion of an elastic fluid, with force and a loud report.
Fekmestatiow, from ferTneniwm, that which is light and puffy ( origi-
nally applied to the process by which alcohol ia formed in saccharine
Ferrdgihous, tvota ferrum, iron ; belonging to, or resembling, iron.
FlLTEft, a strainer.
Floobinb, fromjfuOjto flow; an elementary principle contained in fluor
spar, which is so called from its acting as a flux in the working of
certain minerals.
siGooi^le
APPENDIX. 283
G-HAViTY, from p'avis, heavy ; the natural tendency of bodies to fall
towards a cenlre, usually the centre of the ciirth.
Gkavity, Specific; the relative gravity or weight of a, body, considered
with regard to an equal bulk of some othei' body, whieli is assumed
as s, standard of comparison.
HBTBaooBBBOTjs, frotti bipo!, flitferent, and ylms, kind ; different in nature
and properties.
HontOGEHBOTis, from b/iisi ^i-^e, and ylmf, kind ; alike in noture and pro-
pertiea-
Hydb ATE, from 4d&,,i, water; any substance wWch containa water che-
mically combined.
Hydkogbn', from iJcufi, water ; ani yiry^a, to produce; an inflammable,
colorless, and aeriform fluid ; the lightest of all known substances, and
one of the elements of water.
Htdbo; wlien prefixed to the name of a chemical substance, denotes
that hydrogen enters into the composition of the substance which it
signifies.
Hydrostatios, from dJupi wafer, and in-nrSt, poised; the brancli of Natu-
ral Philosophy which treats of the pressure and equilibrium of non-
elastic fluids, and also of the weight, pressure, &C., of solids immersed
Hypo, from iwi, under; when. prefixed to a word, denotes an inferior
quantity of some ingredient which enters into the composition of
the aubstancB which it signifies.
Hypothesis, from i^d, under, and riflBC, to place ; a principle supposed,
or taken for granted, in order to prove a point in question.
Ignite, , from it/nis, fire; to heat a sabatance to redness; to set on fire.
Imponderable, from in, not, and pondero, to weigh ; that which has no
pereeptible weight.
Incawdbscbnt, from incfindesco, to grow white ; white or glowing with
Ihcrement, from incresco, to increase ; the quantity by which anything
increases or becomes greater.
IHDUOTIOK, BLECTEIOAL, ftom i/t, to, and duco, to lead ; the effect pro-
duced by the tendency of an insulated electrified body, to excite an
opposite electric state in neighboring bodies.
ISERTiA, from inertia, inactivity ; the disposition of matter to remain ia
Ikflahmablb, from in, unifiamraa, a flame; capable of burning with
Insulatiok, from insiila, an island ; when a body containing a quantity
of free heat or electricity is surrounded by noc'conductars, it is said
to be insulated.
IntebSIICES, from inlerstltitcm, a breal: Or interval ; the unoccupied
spaces between the molecules of bodies.
Iodide ; a compound of iodine aud a metal.
lOBiHE, from toi', a violet, and cXlou tlie form or likeness ; a sofl opaque
elementary substance, which, when heated, sublimes in the form of a
violet- colored vapor.
=vGoo(^lc
Isomeric, from 'mi;, eciual, and /ifpoj, a port ; substances wliicli consist
of the same ingredients, ia the eame proportions, and yet differ
essenUally in their propertieB, are called isomeric.
Lamihj?, from lamUia, a thin plate ; extremely JJiin plates, of which
some solid boilies are composed.
Letigatiou, from Ic^is, smooth ; the reducing of hard bodies to a very
fine powder, by grinding with water.
LiG5fiN, from lignum, wood ; an organic principle of which the fibres of
Tegetables are mainly composed.
JjiTuns, a bine pigment obtained from the lichen roccella ; it ia a most
delicate t«st tor acids, wliicli turn it red.
Malleable, from malleut, a hammer ; that which is capable of being
spread oat by hammering.
Metalluroy, from (.sraXXot, a metal, and Ipyon, a work; the art of work-
ing metals, and separating them from their ores.
Molecules, -ab, a diminntive from moks, a mass ; the infinitely small
material particles, of which bodies are conceived to be aggregations.
Mucilaginous ; reeembliog mucilage or gnm,
MuRBXiDB, from murec, a fish affording a. purple dye ; a besutifiil pur-
pla compound,reBultingfrom the decomposition of uric acid by means
Nascent, from naaeor, to be born ; in the moment of formation.
Nitrogen, from p.'rpot, nitre, and ymiriBi, to prodnee : a colorless ele-
mentary gas, devoid of tasle and smell; it is oca of tJie constitnents
of the atmosphere, and also of nitric acid, fi'om which latter circum-
stance it derives its name.
NiTBOOBBODS } containing nitrogen in combination.
Nucleus, from nucleus, a kernel ; the central ports of a body, whicli
are supposed to be firmer, and sepai'ated from the other parts, as the
kernel of a nnt ia irom the shell ; also, the point about which matter
is collected.
OCTOHEDROK, -AL, ft'om 6«-u>, eight, and llpa, a side ; a solid figure con-
tained by eight equal and equilateral triangles-
Olefiamt GAS, from, oleum, oil, and Jio, to become; a colorless gas,
composed of carbon and hydrogen (CjHj), which derives its name
from its property of forming an oil-lihe liquid with chlorine.
Obganic natter, from epyaeot, an organ ; matter of which the organic
5 arts or juices of plants and animals are composed, or which is
erived from such parts by the action of chemical agents, is called
Oxide; a compound of oxygen with a metal or non-metallic body, not
having acid properties.
Oxidize ; to combine with oxygen.
Oxygen, from djS;, acid, and yuria, to pi'oduce; a colorless elementary
gas, which was formerly supposed to be the universal acidifying
principle.
=vGoo(^lc
APPENDIX. 285
Pblltcle, a diminutive irom pdlis, a akin or crnst; a thin crust formed
on the aurfeoe of a solatiou by evaporation.
PeuiCOLirE, from per, through, and colo, to strain ; to strain i^lirough,
Pbbheatb, from permeo, to pass through ; to penetrate.
Phekomenos, from ^nfwjm, to appear } an appearance which is more or
lesa remarkable.
Philosoehs ; trom ^tMa, to love, and iro^.a, wisdom ) the study or
knowledge of nature or morality, founded on reason and esperience;
the word originally implying " A love of wisdom,"
Pblogust^Nj from ^X^w, to bum ; a name given by the older chemists
to an imaginary substance, which was considered as the principle of
inflammability.
Phosphobub, from Jws, light, and **p«, to produce j a highly inflam-
mable elementary substance, obtained from calcined bones, which
'',3 light when placed in the dark, owing to its undergoing a slow
, __AL, from fw^!^ nature ; the science of natural bodies, their
phenomena, causes, and effects, with their affections, motions, and
operations.
pNBUMiTics, from n^rfifn, airj that branch of Natural Philosophy which
treats of the weight, elasticity, and other properties of aeriform fluids.
PoLiRiTT ) the opposition of two equal forces in bodies, similar to that
which confers tlietendencj of magnetized bodies to point towards the
magnetic poles.
Polarized light ; light, which by reflection or refraction at a certain
angle, or by refraction in certain crystals, has acquired the property
of exhibiting opposite effects in planes at right angles to each other,
is said to be polarized.
Pone3, fromuipo;, a passage; the small interstices between the solid
particles of bodies.
pRECIPiTATiou, irom prcecipilo, to fell suddenly, the formation and
separation of a solid substance in a liquid.
Product, from jiro, forth, and duco, to draw; anythingformed from the
elements of another by an operation.
PyBo, fi'Om "rtcfire; when prefised to a word, denotes that the substance
which it signifies, has been formed at a high temperature.
, igarding the properties of a body, and the kinds of
of which it is composed without reference to quantity.
!garding quantities.
Bixm/LTias, &ota radius, a ray; tlie shooting forth in all ditections
from a centre.
BAitErACTiON, from rams, rare, andyiicjo, to make ; the act of causing
a substance to become less dense; it also denominates the state of
this lessened density.
EbctipicaTioh: the process of drawing anything off by distillation, in
order toobtam it in a state of greater purity.
Retiiiotioh, ftom re, back, aadjrango, to break, the deviation of rays
of light or heat from their direct course, when passing through media
of different densities.
=vGoo(^lc
RBPKiaBBATiON, froiii )13, again, and yrii/tis, cold ; the act of cooliag.
Repulsiok, from re, bacls, and pello, to diiye ; that property in certain
bodies, whereby tliey mutually tend to recede from each other.
Salifiable basks, from sal, salt, andj?o, to become ; bodies capaUe of
combining with acida, to form salts.
Sapid, from sapio, to taste of; possessing tbe power of exciting the
organs of taste.
SATUHJiTrON', -ATED, from satur, full ; the solution of one body in another
until the receiYing body can contain no more. A solution is said to
be saturated with an acid or an alkali, when thelatterisaddedin suffi-
cient cinantity to render it neutral, and supeisatural^d when the point
of neutrality has been exceeded.
SoLuTioH, from solvo, to loosen or melt; any liquid whicli contains
another substance dissolved in it.
SoLVEKT, any subBtanee which will dissolve another.
Specific, from species, a particular sort or kind ; that wbich denomi-
nates any properly which is not general, but is confined to an indi-
vidual or species.
Specific gravity ; see Gratity, sPBcinc.
Sublimation, fi^>ni saiUmis, high; the act of raising into vapor by
means of heat, and condensing in the upper part of the vessel.
SnLPHiDE; a combination of a metal with sulphur.
Supersaturate ; see Saturation.
Tebnaby, from teritbrice ; containing three uaifs.
Tbtbahedbow, from rnnraKi, foar, and t^ja, abase or side; a solid figure
contained by four equal and equilateral triangles.
Transparent; a term to denote the quality of a substance which not
only admits the passage of light, but also of the vision of external
objects.
Tbitubate, from Iritui-o, to thresh ; to reduce to powder.
Vacuum, from vacuus, empty ; a space empty, and devoid of all matter.
Volume, from volumen, a roll ; the apparent space occupied by a body.
Weight; the pressure which a body exerts vertically downwards, incon-
sequence of the action of gravity.
Zero ; the luimeral 0, which fills the blank between the ascending and
descending numbers of a series.
=vGoo(^lc
INDEX.
A.
Acetate of lead, reagent,
Acid, acetic, action of rGngenls on, .
araeniouH, action of reagents on,
benioic, action of reagents on, .... 155
boracic, action of reagenlB on, ..... 140
deleoled, 173,180,191;
carbonic, aclion of reagents on, . . . . 140
delected, 174. 195
chloric, aotionofreagenlson, . . . .148
delected, ...... 175, 197
citric, action of reagents on, , .... li?.
formic, action of reagents on, , , . . 157
hydriodic, action of reagents on, . , . . . 144
detected, . . . - - 174
hydrochloric, action of reagents on, ... . 143
uses of, ., 233
impurities in, ..... - S35
detected, ..... 175, IfiO, 137
Table of Hoecific gravitiea of, ... . 355
hydrofluoric 60, 273
hydros ulphtiric, action of reagents on, . . , H5
detected, , . . 174, 179, 195
in of reagents on, ..... 154
impurities in, . . . - . . 2Jj
nitric, delected, ...... 175, 107
Table of specific gravities ol", , , . .258
nitrohydrochloric, . . . . . . 338
oxalic, action of reagents oil. ..... 150
impurities in, ...... 238
D oan oncac^ion^o^reagc , ^ . . ^ '175,180,196
143
173, 180, 198
=vGoo(^lc
detected ,
Table of specific graviii
c, action of reagents on,
impuriliea io,
13 of,
for AllEalimetr]', ,
Acidimetry, , . . .
Acids, claasi final ion of, .
inorganic, acllon of resgents oj
organic, action of reagents on.
Alcohol, . . .
Table of specific gravities of
Alkalies, actionof leagenls on,
Alkalimetry,
Alkaline earths, action of reagents ot
Alumina, action of reagents on, •
blowpipe test for.
111 of reagents on.
leofsi
with,
O'Sulphale of copper,
□tn and platinam, double i
Analysis of simple solubie salts,
simple salts, eolnble in acids,
simple insoluble salts,
mixed soluble saks, .
mixed salts, soluble in acids,
mixed insoluble salts,
sulphate of copper,
chloride of poiasMum,
mixture of sulph. copper and chlor. sodiu.
mixture of snlph. zmc and carb. barytn,
magnesia n limestone,
copper pyrites,
gunpowder,
carbonates, .
Annealing glass, _ ■ ■
Antimony, ojide of. action of reagents on,
distinguished from arsenic,
delected,
Antimoniale of potash,
Anliraonie acid, aetion of reagents on, .
Anljtnonious acid, action of reagents on,
Antiraoninrelled hydrogen,
=vGoo(^lc
Apparstus cleaned,
labelled,
Apothecaries' weigbi
Aqua Regia, .
Arsenic, oxides of, a(
delected in organic mixtures.
sulfihide.
distinguished from antimony,
niaus acid, crystals or, .
sulphate.
Bases, classilicatioi
Balh, oil. .
Benzoic acid, action of reageuts on, ,
Bichloride of platinum,
Biuoxide of nitrogen, prepared and e:
Bismuth detected, .
oside, action of reagents on.
Black flux
Blowpipe flame.
Mouth, how used.
experiments with, ,
Water, .
Boiling -paints of saline solutions,
Borocic acid, action of reagents on.
detected,
Bromic acid, action of rcngenls on.
Bulbs, glass, made,
Btirning tillers,
siGooi^le
aoda, impuriiiea in,
fusion wilh.
Carbonales, analysis of,
Carbonic odd, aciion of reagenlB on,
detecled,
prepared and eiperimenled v,
substances hoateQ in, .
in carbonales, GBti mated, .
oxide, prepared and espcrtmentet
Charcoal support, ....
specific grovily of, .
Chemical equations,
gymbols!'' ^' . ' . ' .
lerma, Glosaaty of,
Chlorio acid, aolion of reagents on,
deleoled.
Chloride of barium,
calcium, .
Chlorine, eslimalion of, .
generated, .
Chromate of potash,
Chromic acid, aoiion of reagents on.
Chromium, oxide, action o! reagems on,
detected, ,
Diohroismofitscompou
Citric acid, action of reagents on, .
Classification of bases and floids,
Cleanliness, importance of.
Cobalt, oxide, action of reagents on,
detected, ....
Copper, oxide! action of reagents on,
ammonio-Eulphate, .
detected,
estimation of, .
brdrated oxide,
pyrites, analysis of,
Sphat'e.BnaVsisof,
a reagent,
Cork boring, ....
Cork, specitio gravity of,
Crucible -jacket,
CmcibiB, platinum,
Cupellation with the blowpipe,
ilh,
with,
ds.
.17
174,
175
, 178
170
183
Decantation of gt
hing precipitates by.
=vGoo(^lc
Deflagniling spoon,
Desiccalion in vncuo,
Dichroiem of sails of chromium,
Discoloraiion of glass, rernoved,
Dislillalionofaninionia,
hydrochloric acid,
Double fillers.
Dropping'!) ottle,
Drying,
F..
Eanhy phosphales, delected,
Equailons,
Eguivaleiils, chemical.
Ether, Table of specific gmviiies of,
Evuporalion, ....
Experiments with the moulh blowpipe.
Ferrideyenide of polassium,
Ferrocyanide of polassium,
Ferrocyonogen,
Fihera, burning of,
ashes eslimnied,
fbUedT^ ' . ■ .
Filtering hot solutions, ' .
Fillering-bloeks, .
Filtering- ring.
Filtration,
Flame, Oxidizing and reducing.
Flasks, uses of, .
Formic acid, action of reagents ■
French Weights and Measures,
., irardwich and Bea
Gas, ammoniacal, prepared and experimented wilh,
hydrochloric
of.
hydrocl
. ofeflBnt, .
Gaseous manipalation.
Gases, dried, .
soluble, preparBli
transferred,
Gasholder, Pepy's,
=vGoo(^lc
Glns9, annealed,
bulbs made,
eyphon made,
tube heated,
hetmeticallj' sealed, ,
Glass- war king, .''.".
Glasses cleaned,
precipilfltins,
Glossary of chemioa! terms, .
Glacina, action of reagents on, .
Gold, perchloride,
oxide, action of reagenis on,
Gravity, specllic ; see Specilii: grav
Gunpowder, analysis of,
Handles of paper for lubes, .
Hardwich's furnace,
Heating in gases,
HydratedBBfls,"e''sl!m"t'ionof"wa'te
Hydriodio acid, action of reagenis
delected,
Hydrobromie acid, net ion oft
Hydrochloric acid, disiillaiior
r".
a of reagents on,
impurities in.
Table of specific gravities of
gaa, prepared and experimen
Hydrocyanic acid, action ofreaeeiits on.
Hydrofluoric acid, action of reagents on.
Hydrogen, prepared and experimented with.
reduc
inofm
Hydroaelenic acid, action of reagen
Hydroeulphale of ammonia, .
Hydros ulphuric acid, preparation of,
Doiion of reagents oi
detected,
apparatus, tnbcs prepared,
Hypoaulpliurio acid, aelion of reagenis on, .
Hyposulphurous acid, aeiion of reagents on.
Indian rubber c<._
Indigo sulphate,
Inorganic acids, action of reagenis (
=vGoo(^lc
petchloride, prepared,
Labelling, necessily of,
Lamp, gas.
mixlure of gas and air,
Rose's,
SolIy'H,
Lead, oxide, action of r(
detectad,
chloride,
chloraautphide, .
chromale, ,
suiphale, ' .
carbonalB, dccomiiosed by h'
osEilale,
pliosphale,
sulphate.
Liquids, heated in lubea,
hermelically sealed in tube
Lilhia,
in of teagenla (
_ _...o-phosphate of, . . . . .05
detected, 173, i9S
none, analysis ot, ..... 236
inof reageiilB on, ..... 154
siGooi^le
it for.
Msnganic acid, action of reagents on,
Marble, specitio gravity of,
Marali'a tsBt for arssoic,
MeaButea, Jinperial,
weight of wolcr conlaine
cubic inches coniained in
Mercury, protoxide, aciion of lengents on, ,
peroxide, sctiou of reagenle oi>,
detecled, . . . .
perchloride, reagent, ■
red oxide, decompoaed by heat, ,
periodide,
Metallic oxides, actioti of reagents on,
Melbod, importance of, .
Microcosmic salt, . . . ■
Molybdenum, ojtide, aciion of reagents on,
Molybdic acidi action of reagents on,
Mouth blowpipe, how uaed,
experimenia with, .
Muriate of ammonia, formation of.
Nitric aind, disiillati
cobalt, .
potash, impuritii
silver, impurities
iciiic gravine
e pared
;e of making.
Oxalate of ammonia, uses oif
Oxalic acid, action of reagents on,
impurities in.
Oxidizing flume, .
Glides, metallic, reduced by hydrogen
lageij
Oxygen, prepared and experimented with, ,
siGooi^le
Palladium, oside.aclionofteogeiitaon 268
Pepya' gaeliolder, ....... ^4
PerchloriiiB of ^old, . . . ' . . - ■ 351
of iron, preporEd, ,,.... 74
a reagent, ..... 24S
of mercury, ....... 250
Fhosphttiea, earihy, detected, 178, 139
Phosphate of eoda, . _ 246
of soda and ammonia, ..... 3*1
Phosphoric acid, action of reagents Oil, . .... !33
detected 176, ISO, lyfi
Phosphorous nciil, aclioti of reagents on, .... 274
Plalinnm, oxide, action of reagents on, ... . 268
bichloride 251
crucible 183, 215
Pneamalio trough, . ....... 37
Polosh, oelion of reagents oti, . . . . . . 88
uses of, 343
detected 173, 194
impurities in 243
Table of spedlic gravities of, ... . 359
chromate, ....... 244
nitrate 243
red pruBsialB, ...... 245
yellow prusaiale, ....... 245
Potsseium, estimation of, ...... 320
cyanide, ....... 245
ferridcyanide, ...... 2^5
ferrooyatiide , ....... 215
iodide, ....... 214
and platinum, double chloride of, . . . .89
Precipi (at ing-gl asses, ....... 207
PrecipitateB, cryslallitie, precanlioiis respecting, . .89
dried 211
filtered 207
washed SOi)
Precipitation, precautions respecting, . . . .89, 184, 307
Prelirainary examination of solids, ..... 1«>
liquids 165
Protoohloride of tin, ....... S50
Prnssiati blue 110
Prussiates of potash, a4ri
Pulverisation, . . . , 201
Pyrites, copper.quanlitative analysisof, .... 229
Q.
QualiiaiivG analyses of simple soluble sails, .... 168
sails, soluble in acids, . . 176
insoluble G ah s, . . .161
of mixed sails, ..... 163
soluble in water, . . .185
soluble in acids, . . 197
insoluble in water and acids, . 203
list of salts for practice in, . . . 27?
=vGoo(^lc
operations in, . . . . . 204
■e^^sui
of aulph. zinc andcarb, buryla
of mognesian lirtieslone, .
of copper pyrites,
ilph. copper, nnd chlor, sodiui
Reducing ilnnie ...
Reduclion lest for araemc, .
Reinsch's leal for orsemc,.
Results, caleulalion of,
Rhodium, oxide, action ofrcagcnla o
Rods, glasa, cut,
fltirring, made, .
Kulea, general,
. 4
. ' . 13
21
. ar,
. ' . 5
■ . ' 1
Saline baths
Sails, eslimation of water in,
Toble showing the aolubilirjf of, ....
for practice in qualitalive analysis, ....
^clenic acid, action of reagents on, ....
Selenious acid, action of reagents on, ....
Silicic acid, Dctioti of reagetits on, ....
detected, ...... H.'i, 1
Silver, oiide, action of reagents on, . . . , .
Table of specific gravities of, .
biboratB, '.'.'.
phosphate.
Solids, preliminary examination of, .
Solly's Lamp,
Soluble gases, preparation of.
Solutions, saline, boiling-points of, .
Specific gravity of solids, .
siGooi^le
IN OCX. 207
Specific gravity, effecfs of (empcraiure on, . . , .68
SlaiiiB on glass l-emoved, ..,.., 49
Starch, HO In tion of, ....... 251
Stirrin^.rods, made ....... 49
Stronna, action of reagents on, ...... lOO
detected, ....... 173, 1^3
blowpipB lest for, ...... 101
Succinic acid, action of reagents on, . .... I!>:>
Sulphate of copper, analysis of, ...... 219
a reagent, ..... 249
of indigo, . . . . . . .2^1
Sulphates, blowpipe lest for, ...... 137
Sulphides, action of reagents on, ..... 145
detected 179, 20O
Sulphur, estimation of, 230
Sulphuretted hydrogen, preparation of, . . ■ . . 236
action of reagents on, . . . 145
apparatus, tubes prepared, . . .54
Sulphuric acid, action of reagents on, .... 137
detected 174. ISO, lys
Table of specific gravities of, . . . 255
desiccation over, .
impurities in,
Sulphurous acid, action of reagents i
Symbols, chemical, .
Syphon lube, made,
Table, strength of Am
flydrochloric acid, ..... 257
Nitric odd 35(i
Potash, 259
Soda 259
Sulphuric acid 555
showing Ihe aciion of reageiiis on oxiics and acids, . 2M
boiling-points of saiine solutions, . , . 215
solubilily of salts 263
Tartaric acid, action of reagents on, .... . 151
uses of, 339
impurities In, ..... . 2'i3
Test-tubes, made 51
cleaned, ....... 23
Tin, detected, . . . . . . . . 170, ISS
protoxide, action of reagents on 133
peroiiide, action of reagents on, .... 134
protochloride, reagent, ...... 250
cryatalaof, ....... 135
Trough, pneumatic, ....... 27
Troy weight, ........ 253
Tube diatilUtion 166
glass, joined, ....... S3
=vGoo(^lc
2EI8 INDEX.
Tubes, glass, hei'melically sealed,
lor blowpipe caperiiiients. .
syphon, made,
Tungsiic acid, action of reagents on,
U.
Uranium, oxide, action of reagents on, .
dbtdledT"' / ™*. ■
Water blowpipe, .
Water bath,
Weigliiog, . . , .
Weighis and Measiires, Tables ot
French,
Wooden filtering-blocks.
Working glass,
Zinc, ojtide, action of reagents oi
delected,
blowpipe test for.
siGooi^le
siGooi^le
siGooi^le
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OtoerraUonB. Trtilb tuition, retlsBfl onii mnoh eitended. by Robert P. T
ProfeBor of Materi* MeiLea fn tho lliiUdElphiu Coilcge of PLiHuacy. lu ei
Tolume of 296 pages.
noarij 900 closely prialed pages.
VLIST (AUSTIN), M.D.— PiFiBicst ;
KEROTIHB0SCWTLL!AM),F.B.8.— A
IfRinK {CflABLTlS), M.D.-Ee(
iruii oi. One iDlume, royal :
F*L AFTEmoj'S : their DiBgaorfs »n.
FOWNES (GEORGE), Ph. ».-
rojsl 12mo. volume, of oyer B
iteil. »illi ASiliriouB, hj Unh«rl Br
iSOpages, withlSl wooa-cuB, Blib
"si'szrs-i'S
OS C0NSII5IPTION.— BjI^mH
iiqie, eltraelolU, {.V'm Xtady.)
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6 BLANCflAHD A LEA'S MEDICAL PUBLICATIONS.
GIIAHAJI (THOMAS), P. B. a,— The Kt.fments nFlNtinaABic CiiEHiBTar. Innluatog the Ap-
Ifladou edition. lioL Svo., or oier SODpB^B,eitraDlD[h.' $4.01.
PlBT I. (laU^ imiedi, lugs Sn^ OO pnges, ISS UluetrBtioiUI. $1.S0.
PiM IL (luia readg), U mntcli, over 400 pigen. (2.S0,
OKOSS (SAMCEL D.), K. D,— A PB.ICTIOU. TBEtTlBB OB IBB DiBSJSRB, InjbWEB, AND MllFOil-
Q ROSS (SAHDBr, B.), M
GLUGB (GOTTLIEB), M. B.-Ab ATHa of Patholoo™l HiETOLOar. TrBni.Uted, irith Not™
Mill AddLtions, by Joseph Leldy, M. D., ProfeBSor of Anaminj- in Iho University of I'eim.
eylvnnU. In one volume, Ter; Urge Imperial g,uarti>, nltb HO figures, plain Bud wloreil,
eiUFFTTH (ROBBBT E,), M. D.— A UmveBSii, SoMiouBT, coolahilng the methods of Pre-
nnd PharmoMutiBla. SacoEd edition, thoroughly revised, with nnniBrone Addition", liy
hobert P. rhomiLS, M. D., Profwaor o( Mawria Medlw in the Philadelphia College of fhu-
GRIPFITH (ROBERT B.), M.r. — Mekoal Botant; or, n DeseripUoa of all the more im-
HAllItlSON (JOHN), M.n. — AkEssit TomAKM a Coreeot Theoei of ths NESvoua Stbtbi
nUQHES (H. MJ, M. D.— A CUNICAl iBTPODCrCTiOH TO TSB PnAetlCE DP AnaCDLT^IlOl', »t
otll'<r Afudea of Physicnl DiBgnOiis. in IHnjaeen Df tile Lungs and Hiairt. Second Ameiici
BOKNBU (WILLIAM B.), M.D. — SPKIAI AMTomr ABpHi6»oio«t. RIglith cdifion. E:
hatidsomdj'^pSntoJ.wUh oyer 'sou illuBtrulionE. " " ™ '"*'
IIABBRSirOW (S, 0.), M.D.— Pat»
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edition. In oua hindsoios ootavo volume, eitra oloth, of atout 500 pases, (Jiui Jjmai)
J0NB3 (T. WnARTON], P, B. 8,— The PniNurPLEa ind Psactioe of OparHjiLiiin MEDicrja ihb
w'ui 110 niuslmUo ™' ■ ■ " ' ' ■•
JONES (C. RANDFIEL1)),F.R.B, AND BDWAIID H, SJEYEKINS, M.D. — A MiSOAl Of
of ii«iclyV60paEeH,l8ithev. (iii^ Jisiiai.)
KNAPP(F,XPb.D,— TE0Hsoi™i;Dr, ChediiflttrBppiledto theArlssnd lo Mannfaoturen.
Bailed, »ltb nuniBIoas Notes ind Additions, bj Dr. Bdmnnd Ronulda .nd Dr. ThomBS
LRHJIANN (0. 0.). — PHiBioLoaioAL Chehibtfy. Translatfll! from the peoood editLoo bj
tlous. (Just Laiud.)
LEHMANN (a. 0.). — MsHDJL at Chemical Phtsiohisi. Translated from the Germ™, nllh
tA ROOnii (R.), N.D.—P.'iEnuoinA! Its Supposed Connectios, Patholc^lcal and EtlnloglcnL
with Autumnal Perers, inclnding an Inquiry into Uie ISiiatonce aud SlorWd %euoj of
Uularla. In one handsome octaio Tolume, extra olath, of iOO fKSee.
lA ROCRB(R.), Id. D.—TBLLa«FErEi{, considered In Its HlHtniical, PathoIo«Iul,EllDli))iI«f.
Philulolphll from 168B to JfiM, with an Eianiinotlon of the Counections tftween It nud
lEi^ionH. In two lurge and haiidsome octavo volumes, of nearl; 1.500 pagea, e£tra clotki.
LAWRKNCE (W.), P. R,S, — A TrauTisE oh DisE.isEa op the Eve. A neiF adition, pdlted.
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MEIGS (CHAIllES D.), M. I,— Woman: b™ Dibrasfb Im thfiii niiTEoiKa. AS,
torea to hie Class. Ibird ond improvwl edition. In ono Inrae »nd l«81ittC.
WBIOS (CHAELBS D.), M. ».— OnsiwraicST THE SfliEHOE and thi Ari. Pern
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MBIQ9 [CHARLES D.), M. T>. — A Tbiitihs OS Aci?iB«SDCiniosToDi3EAaiB m i
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jaLLBR (JAMBS), F. It. S. B.— Prinotpt.eb op SnRaRRr, Fouvlh AmiTloan. fron
and nivtsed IMlnbui^h edition. Id oue Israe sod r»r; benutifiil rolame otlW
240 wquiate iUaJttTitiona on mod.
MILLER (JAMBS), P. E.S. E.— Tun Phaohci op Susciecy. Fonrtb Amerinra. fro.
JJidlnliarKh «,(ilion. lidik'd, with Additions. Illn8tr,vt«l bj 301 imBmyiuaB on
MALGAIGNB (J. E.). — Operative SmGEBV. bnBed on Normal ard Paflinlosloal
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Uona OQ wood. lu ons baudsane ocl»TO voluniB of neatly aoo pas^s.
MOHR (FHANOIS), Pb, D., and KRDWOOP (THEOPHTLnS).— Prapiicai Pbakhaot. Com-
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Laboratory. Edited, with ojtteuttlve AddfUonB, bj [^tof. WUHftm Procslar, of tho Phiradol-
phin Cotl^ of Pbanuat^. In one handsomelj'-prJaEud octavo volnme, of &T0 psgea, with
orar SOD ena;nning8 on wool).
ilACLISE (JOSEPH) .^SmsiCAL hskvan. Formlns one Tolnme, ver)> laive Imperial qAinrln.
With ris.lj-ei^'i'i large and Bplflndid P!RtM,arBno in tbs bwi rtyle, and Saautlfullyraloreii.
natory lettnr-preiu. Stroniil; Hnd faDndsoniely .b^und ia eitn cloUi, boliig ono of tbs
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sod en1ar|;el BngtJ^li editloiu Wktb two ffitqulflilo coloured platBtc find Dmneroda wood-
MiTNE (JOHN), M.D.-A DraptsSATORr isD Thbsapeotmal Kkhehbkascer, Comprfslng
IB fW.l.M D. — A pElCtlOSL Teestibb OB DBEiasa «BD Ibto
preflxai an AnntoniiHil Inlrodnction, bj T. Wbarton jDnet
D. Ill one lery large and hondHOmo octayD volume, with uumi
KM pages, witb SM llliutraClouE on nood. StroDgV bound
lnl«»tlier,irtthriaMd
bands.
lEII
:,L(JOHW).M.D,-
■E^x,
"a,™lol.
'"Cba
mS.i»™
ilotoS pli
iel:
[QAN (J. MOOEB),
uine,eitmdoth,w
S^
i^cf^
^r'^T^^
lELl
[OAH (J, MOORE),
s) J2mo, volumo, ol
"mp'^*
r^x.
-="^— "
IWE
N(PI«)F,B.)-0«
TazDlTF
EOHTBC
^^rz.
:bb SESLB'
lOH. On
PABSBK (LATIGSTOIf).— The UoBIBH TneATUtnf OF SiPaiLmi Bishbes, both pBimabi lira
S£{»N1>4nr; QQiD prising tba TreatmeDt of Coustitutional and CODfirmed Syphilis, b; aaafe
BDd sucocEnful melbod. Witb nuioeraiiB Caees, Formnlffi, sud Cllnieal ObeervaUoDa.
From Chs Uiiid ana enUiel; lewritUD Laodon edition. In one neat octaTO volume.
. PBRBIRA (JONATHAN), M.D. — Thb Blsmbjub op Matebu MeDio* and TnEEAPBurics.
Materia Medics. BOtlod, with AdditloBS, by Joaspb C^ceou, M. B., Professor of Maturii
Wadics and Pharmacy la tbu Unlvarailj of Peonsylvaala. In two Tfty large octavo lo-
iHmeB of 3100 pi®s, on Bmali type, wilh over 430 illusttalions. (Nmo CSiinjjtele.)
PABRISO (BBWARH).— Ah IsiKocnCKON TO PBAonoAi Phahhioi. Beslfnod aa a Tait-hook
ibttlie Student, ana as a flnide for the Pbysloian and PharmacauUst. With . many Pw-
PBASELBB (B^nO, W
~ ittjorpeanKyTvaaVn,
fli m Uluat
PIRJIIB (WILLIAM), P.n.S.1
FensByli^nla lioBpitpJ, £a.
KAMSBOTHAM (FKANCI8 Tl.), M.B
AND SomiEBV, hi retUraace to the Pn
roughly revined by the author. V
ul flgotea. (Just Iniud.)
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